


Compatible - A Romantic Science Fiction Thriller in Four Parts

by the1918



Series: Compatible [1]
Category: Captain America (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Alpha Steve Rogers, Alpha/Beta/Omega Dynamics, Alpha/Omega, Alternate Universe - Canon, Alternate Universe - Modern Setting, Anal Fingering, Anal Sex, Angst with a Happy Ending, Barebacking, Bearded Steve Rogers, Biochemistry Porn, Blow Jobs, Captain America Steve Rogers, Captain America Steve Rogers/Modern Bucky Barnes, Consent Issues - See Chapter Warnings, Dubious Consent Due to Biological Imperative, Engineer Bucky Barnes, Fake Science, First Time, Held Down, Hurt/Comfort, Knotting, M/M, Mating Bites, Mating Cycles/In Heat, Modern Bucky Barnes, Not Canon Compliant, Omega Bucky Barnes, Omega Verse, Possessive Behavior, Possessive Steve Rogers, Post-Avengers (2012), Protective Steve Rogers, Rimming, Rough Sex, Shrunkyclunks, Size Difference, Size Kink, Smut, Tooth-Rotting Fluff, Twink Bucky Barnes, Which is not talked about beforehand but hey the serum is a total deus ex machina, feral steve rogers, just fake biochemistry, like there are no robots, not actually science fiction
Language: English
Status: Completed
Published: 2019-09-11
Updated: 2019-09-11
Packaged: 2020-10-14 08:00:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 33,081
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20597390
Author URL: https://archiveofourown.org/users/the1918/pseuds/the1918
Summary: He watched then as Steve closed his eyes and took a deep inhale.“What’s up?” Bucky asked.And Steve’s eyes fluttered open slowly, and he gave Bucky a soft, handsome smile.“Nothing,” Steve replied, finally exhaling as he looked back into Bucky’s eyes. “I just really like how you smell when you’re happy.”---When young nanotech engineer Bucky Barnes finds himself falling head first in love with none other than Steve Rogers, he ends up getting a lot more of the Alpha than he-- or science-- could ever have imagined possible.Or, the PWP that accidentally grew a plot.





	1. Prologue

**Author's Note:**

> This fic was born into the world as a disgusting, smutty PWP plot bunny full of every a/b/o trope in the book. Then I watched it accidentally grow a plot and even sprout some world building. I apologize for what I have created.

** Prologue **

\---

In twenty-first century, it was generally taught in all high school health classes that most Omegas had two heat cycles per year. 

Contrary to popular portrayal in early movies and television shows (almost all of which were written and produced by Alphas), Omegas did _not_ keel over if they did not have an Alpha to help them through their heats. It made the heat an easier time, certainly, and it could be incredibly pleasurable if both Alpha and Omega were enthusiastic and consenting participants, but it wasn’t strictly _necessary_. Most Omegas made out just fine, if not a little itchy and hot. 

Likewise, Alphas did _not_ enter a rut from simply being around any Omega in heat, even if it was their bonded partner. In fact, the vast majority of Alphas would never enter a rut in their entire lives.

And, according to mating and health scientists, all of this is held to be true—provided, of course, that the Alpha and Omega in question were not _Compatible_.

\---


	2. Act I - Exposition

**Summary for the Chapter:**

> Bucky thinks back on the first two months of his and Steve's relationship.

**Notes for the Chapter:**

> This first part is 100% tooth-rotting fluff with an injection of smut. 
> 
> No content warnings (i.e. dub con) apply for this part.

**Act I - Exposition**

\---

Bucky Barnes woke up with a smile on his face and a warm, hard body at his back.

He could feel the mouth of said body drooling a little on the spot where it pressed against his shoulder, the owner of the mouth still fast asleep. Bucky’s eyes glanced at the digital clock on his nightstand. It was just past seven, a little earlier than Bucky usually woke on weekday, but now that he was awake he knew he wasn’t going to be able to fall back asleep. He drew in a deep breath and allowed himself a moment to luxuriate in the warmth of the strong arms surrounding him, the softness of his sheets, and Steve’s sleepy, smoky, quintessentially Alpha scent teasing his nose.

If the drooling should have grossed him out, it didn’t; the strange intimacy of it just made Bucky want to roll over and kiss the other man awake. But he didn’t, because he had been selfish the night before and kept Steve up late, much later than he should have considering the fact that Steve had already been a little sleep-deprived and also needed to catch a plane later this morning. Steve needed his sleep.

So instead of waking him, Bucky carefully extracted himself from the larger man’s arms and padded to the doorway. He allowed himself a brief look back at his boyfriend snoozing contentedly on Bucky’s bed. His leg was sticking out from underneath the comforter and his body was all long lines and muscle, naked skin but for the beard covering his jaw and a wonderfully tight pair of boxer briefs. Bucky sighed happily and stepped into his bathroom.

He stepped under the warm spray of the shower and began stretching the sleep out of his muscles. When he reached over to the clutter of shower products along the shelf, his eyes passed over his bottle of Beta wash that sat, mostly full and unused, next to the lightly-scented shampoo that he knew Steve liked. Bucky never really bothered to use scent-blocking products anymore, hadn’t used them much even before he met Steve; but, as an unbonded Omega, it was useful to have a bottle of Beta wash around just in case he was headed to a concert or somewhere with a lot of sweaty bodies leaking pheromones. 

As Bucky worked the shampoo through his hair, his mind flashed back to the first time he had smelled Steve Rogers’s scent, marveling at the thought that it had only been about seven weeks prior. _So_ much had happened between them in those two months. He’d met Steve. He’d _liked_ Steve. Steve had liked _him_. The thought sent a happy little shiver down his spine.

It had been a Friday morning and Bucky had been busy at work, tinkering around in his favorite place in the entire world— the nanotech lab at the Stark Industries research facility in Manhattan. 

_Bucky had been working alone that morning, and his focus had been completely on the tiny, microscopic robots that had been skittering around in fantastic patterns in the glass dish in front of him, when he’d suddenly heard the lab door behind him open._

_“Hi,” a deep voice had spoken from the direction of the door. “Is, uh— is Tony here?”_

_Bucky had spun around in his chair towards the unfamiliar voice. When his eyes had landed on the source, he’d dropped his pencil. _

_The man standing the doorway to Bucky’s lab had been none other than Captain America._

_Well, it wasn’t his lab, exactly; like everything else in that enormous building (‘Avengers Tower’, as the press had taken to calling it), the Stark Industries research floors were the property of Tony Stark, Bucky’s boss. But, given that every project in that particular lab had been placed squarely (and a little inexplicably) under Bucky’s direction, he had no problem calling it ‘his lab’._

_And so Bucky had sat in his lab, staring at Steve Rogers, for a full five seconds before finally remembering to speak._

_“Yeah. Uh. No. Tony is, um.” And Bucky had mentally slapped himself for forgetting how to string together a sentence. “I haven’t seen him yet today. He, uh.” He’d looked down at the clock on his FitBit. “He’ll probably stop by soon. He usually does, on Friday. To check in.”_

_“Oh. Okay.” _

_And then Steve had stepped in, looking around the lab a little, expression obviating a bit that he had never been on the research floors before. _

_“Do you mind if I wait here?”_

_“Um,” Bucky had started, too slow apparently, because then Steve’s cheeks had immediately begun to flush pink. _

_“I can be quiet!” Steve had interjected. “Sorry, I don’t want to disturb your work, you look really busy, I can—”_

_The image of a strangely meek super soldier stumbling over his words in front of him had completely taken Bucky aback._

_“No, it’s fine!” he’d returned, his voice betraying his nerves with an embarrassing little crack. “Really, I don’t mind at all. I could use the company, actually. I, uh. Don’t get out of the lab much these days, and I’ve been pretty much working alone all week.” _

_It had been the honest truth, but he’d hoped that he didn’t sound too eager to have _Steve _fucking_ Rogers_ be that company._

_“Oh.” Steve had given him a relieved— if still a bit nervous— smile and walked further into the lab. “Great. Thanks. I’m Steve, by the way,” he’d said as he sat down in an empty chair at the lab bench adjacent to Bucky’s._

_“Nice to meet you Steve, I’m Bucky.”_

_“Hi, Bucky. It’s nice to meet you, too.”_

_Introductions aside, they’d traded shy smiles and a few moments of skittish silence. Steve’s eyes had shifted down to the silvery, skin-like covering encompassing Bucky’s left hand and wrist where they were peeking out below the cuff of his long sleeves._

_“Do you want to see it?” Bucky had asked earnestly, lifting his left arm and rolling up the sleeve to his elbow. He had figured it was as good of an icebreaker as anything else his jumpy schoolgirl brain could come up with in that moment._

_Steve’s eyebrows had shot up, body jolting a little upon realizing he’d been staring. “Oh! I’m so sorry, really. I just noticed and it. Looks really neat.”_

_But the adorable blush had melted Bucky, along with the grandpa-esque slang (who the hell still says ‘neat’?) that reminded him that he was talking to a one hundred year-old man._

_“No, no— it’s cool, really! I like to show it off.” Bucky’d rolled his chair in closer to show off the arm._

_Steve’s shoulders had sagged in relief as he’d leaned in to look. “What is it?”_

_That close, Bucky had been able to catch Steve’s scent. It was incredible, intoxicating from the first moment he’d smelled it; cedar and charcoal and a hint of bergamot, and something else Bucky could only describe as _Alpha_._

_“It’s prosthetic skin, made of a special metal alloy invented just for this. It goes up a little past my elbow.” He’d moved his arm around, opening and closing his fist so that Steve could see the way the prosthetic covering adapted and shifted as it moved over the underlying muscles, just like real skin. “When the—you know, _aliens_ came in 2012, I was an intern working on one of the old lab floors and my arm got burned pretty badly in a building fire. It was in a really nasty shape after that.”_

_Steve had leaned forward, awed, and hovered his fingers over the inside of Bucky’s left wrist. Bucky’d pushed his arm closer in Steve’s direction._

_“You can touch, if you want. I can feel it, just like real skin.”_

_Steve had looked up at him and given another sweet smile before looking back down. Then, just as Steve’s fingertips had made contact with the glittering surface of the graft, the lab door had opened abruptly and Steve had pulled away with a jump. _

_And Tony Stark had come striding into the lab with all the billionaire playboy confidence that Bucky had come to expect from his boss._

_“I see you’ve met one of my greatest creations, Cap!”_

_“I’d really appreciate it if you didn’t keep referring to my arm as ‘your creation’, Tony. It’s _my_ arm now.”_

_“Be that as it may, Buck-a-roo, I can’t help but brag about being the greatest mind of the decade in the field of medical technology, can I?” Tony had made his way forward to come to a stop next to them. “What do you think, grandpa?”_

_“It’s incredible. Really.”_

_“Experimental platinum-vibranium alloy, applied to each individual cell with an army of my little baby nanobots. The procedure took— what was it, Bucky Bear? Nine hours? But it’s over a hundred times more sensitive than grafts of living skin, and no chance of rejection. Plus—it looks really, really cool. Only the coolest for my best engineer.” He’d leaned over then to give Bucky a proud pat on the shoulder. _

_“Yep, Tony.” Bucky had given Steve a little wry smile as he humored his boss. For as much as the guy could annoy him, he really was eternal grateful for what Tony had given to him. “You make me look good.”_

_“Damn straight I do, and you’re welcome.” Tony had turned to Steve then. “Well, thanks for meeting me down here, Cap. Ready to skiddadle?”_

_“Sure.” Bucky had felt a pang of sadness to see Steve leave his chair and move towards the door with Tony. He’d stopped on his way out and given Bucky a look back. “It was really nice to meet you, Bucky. Thanks for letting me keep you company.”_

_“Of course, any time.” He’d tried a last-ditch attempt at a flirtatious smile. “See you around, Steve.”_

_“Bye, Buck.”_

The last of the suds washed out of his long, shoulder-length hair and down the shower drain. Bucky stepped out the shower and toweled off his hair before leaning over the sink towards the mirror, setting to work on his morning skin care routine while Steve dozed in the room over. 

—

**_Popular Science Magazine_, November 2016**

**"Mating Science: A Brief History"**

**Guest Author Dr. Peter Harlow, M.D. - Brooklyn Academy of Family Physicians **

Most anthropologists and paleontologists generally agree that, historically, more than half of the global population has always consisted of Betas. 

Due to the makeup of the majority population and the fact that the field of mating science was not truly born until the Cold War period, the public understanding of Alpha-Omega mating behavior was drastically different before the scientific advancements of the mid-twentieth century. Before then, almost everyone could tell you that they had _heard_ the story about some Alpha going crazy because he was held back from mating with an Omega in throes of an earth-shattering heat, or perhaps the one about the mated couple that was thrown out of their boarding house for breaking too many bed frames. And yet, very few people could say they actually _knew_ the Alphas and Omegas involved in these stories. 

An experimental survey embedded in the 1960 U.S. Census found that as many as 94.3% of bonded Alpha-Omega pairs did _not_ report having ever experienced a “Mating Event of Exaggerated Significance”— the definition of which was poorly stated by the survey creators, and the phrasing awkward. Despite it’s flaws, the 1960 Census was significant because it was the first documented attempt at a large-scale scientific survey on mating behavior. When the results were released, it created the first public debate about the popular understanding and opinions on mating behavior, and later spawned the first wave of the Omega Rights movement. Nonetheless, the seeming abundance of anecdotal evidence concerning raging heat cycles and uncontrollable Alphas in rut continued to permeate the public conscience. 

—

Bucky finished brushing his teeth and toweled off his mouth. Humming to himself happily, he donned his green, waffle-weave bath robe (which was maybe a little too-short and slutty, but hey, he liked being a little bit of a minx when Steve was around) and moved back into the bedroom. As he headed towards the kitchen he looked over at Steve; the big, bulky Alpha was still fast asleep on the bed, face now buried in Bucky’s pillow. He closed the door behind him and made a mental note to wake up Steve after another thirty minutes.

He continued on into the kitchen and got to work making the coffee. As he worked, he found his mind wandering back again to the beginnings of his and Steve’s relationship.

After their first meeting, Bucky had found that he couldn’t _stop_ thinking about Steve Rogers. The Alpha has quickly become the new star of his day dreams, and even more so of his wet dreams— which were increasing in frequency at an embarrassing rate. 

Then, on a Friday morning not three days after their first meeting, they’d bumped into each other for a second time. Bucky had been waiting at the pick up counter inside the coffee shop down the street from his lab when a familiar, burnt cedar smell had wafted into his nostrils. He’d turned around swiftly and had immediately come face-to-face with the Alpha who’s face (and body) had been tormenting Bucky’s thoughts for days. 

_“Hey, Bucky. You come here a lot?”_

_“Uh, yeah. Almost every day, actually. You?”_

_“Sometimes. Pretty much always with Natasha, though. That woman consumes a frightening amount of espresso.”_

_Bucky was used to Tony being a staple character in his life, but for some reason the reminder that Steve was an _Avenger_ who hung around _other Avengers_ and casually called them by their first names had thrown Bucky for a loop. He’d stopped to look around at the people in line, failing to spot the redhead known as the Black Widow._

_“She’s not here,” Steve had supplied, seeing the question in Bucky’s expression. “I, uh. So I know I’m probably a total creep for doing this, but I may have been walking and seen you come in here.” He’d ruffled his hair a little and looked at the ground, and _wow_, how Bucky had been _fuuucked_. “I really did like talking to you the other day.”_

_Bucky’d suddenly had to stop and force himself to ignore the swarm of over-caffeinated butterflies that were suddenly wreaking havoc in his stomach. Whether by a stroke of luck or sudden blessings from above, Bucky had next managed to gather his wits and lay down his best impression of collected, cool, and flirty._

_“Well, lucky for you, I kind of have a thing for creepy Alphas that follow me into coffee shops.” He’d flashed Steve a smile, then preened at the way his joke had elicited a warm, deep laugh. Then, the barista had called his name and Bucky had turned to retrieve his latte. “You wanna grab a table together after you get your drink?”_

_“Yeah,” Steve had smiled back. “I’d really like that.”_

While the coffee brewed, Bucky pulled out the toaster and reached into the breadbox. He set out to make breakfast for the two of them— one fried egg for him, six for Steve—so that Steve had something in his stomach before he had to run out the door.

Looking back, both him and Steve had recently taken to referring to that coffee shop meeting as their first date, even if their real first date hadn’t technically come until a tad bit later. They’d sat, tucked away at a corner table, and the conversation had flowed between them easily. Bucky had at first impressed himself by acting as though he wasn’t even thinking about the fact that he was having coffee with Steve Rogers, Captain America—but, soon, he hadn’t needed to act anymore; Steve Rogers had quickly transformed in front of his eyes to just Steve, the sweet, funny Alpha who laughed at Bucky’s jokes and asked him lots of interested questions about his engineering work. After almost an hour of talking, Bucky had reluctantly needed to excuse himself— he’d been _way_ late to work— and Steve had stopped him on his way out and asked him if was interested in a date.

_“Uh, yeah— yes,” Bucky had answered, grinning ear-to-ear and unable to stop himself from blushing. “How about this weekend? I don’t really have any plans.”_

_“Perfect.” And then Steve had fucking _winked_ at him, and it had been all Bucky could do at that moment not to grab the Alpha and kiss him in the busy Manhattan coffee shop. “Is tonight too soon?”_

_“No, not at all. Tonight is perfect.”_

_And then they’d exchanged numbers and set a time, and Bucky had distractedly moved along to his work in the lab, where he’d accomplished absolutely nothing the entire day._

—

**"Mating Science: A Brief History", ** **Guest Writer Dr. Peter Harlow, M.D. - continued**

The dichotomous relationship between statistical observation and neighborhood gossip wasn’t solved until 1966, when a pair of bold Omega scientists unraveled the mystery and published a paper on the phenomenon now known as _Compatibility_. The original publications on the subject were an unfettered mess, but the term was better clarified and more properly explained the 1978 volume of _Applied Mating Science_:

**_Compatibility_**_ (noun): The comprehensive term to describe a set of biochemical phenomena appearing in Alpha-Omega pairs that evoke non-typical mating behaviors in their mates. Omegas in a Compatible pair will enter a Heat exhibiting a significantly increased libido compared to normative subjects of the same designation. In addition, Alphas in a Compatible pair may be highly irascible and frenzied (refer to _“rut” _in Section 4.9). [Editors note: It is unknown whether the original authors intended to emphasize the exaggerated Heats by use of capitalization; however, as of 1978, this form is generally accepted by the mating science field as the proper denotation for the mating cycles experienced by Omegas in Compatible pairs.] Compatibility may be confirmed in the laboratory utilizing blood samples from Alpha-Omega pairs and the Faber-Horowitz sequencing method, which will indicate either a positive or negative result. Compatibility is a function of the pairing rather the individual; an Alpha and an Omega that are Compatible together will likely exhibit normative mating behavior if paired with other partners. Based on laboratory studies, it is estimated that approximately one-fifth of all Alpha-Omega pairs globally qualify as Compatible. _

_—_

Bucky set down the plates of eggs and toast on the breakfast table before turning back to the stove to check on the bacon. He knew that Steve would shoot out of bed the second he smelled the crispy pork cooking, which is why Bucky had taken the liberty of stuffing a large towel underneath the bedroom door. His man needed to sleep.

Their first date (well, their _real_ first date) had been like something out of a fairytale. Steve had texted him at eight o’clock on-the-dot to let him know he was on the street outside his northwest Brooklyn apartment building, and when Bucky had descended the stairs he’d been floored to see Steve on a fucking _motorcycle— _all black and chrome and shiny and classic-looking.

_“Um,” Bucky had stammered out, anxious but unquestionably aroused._

_Steve had chuckled a little to see his expression. “Don’t worry, I’m just gonna park it here for now. Our dinner reservation is just a couple of blocks down the street; we can walk it.”_

_Steve had been dressed just like one of his wet dreams— dark-wash jeans, black button-down with rolled-up sleeves, classic leather loafers, perfectly trimmed beard. Bucky had pinched himself before walking over to greet the other man in a hug (and _god_— there it was again, wood and smoke and loose-leaf tea). Maybe he’d shifted his nose a little closer to Steve’s scent glands than was strictly appropriate for a first date._

The mediterranean restaurant Steve had picked that night happened to be one of Bucky’s favorites. They’d laughed and flirted and shared crazy stories over baba ganoush and stuffed grape leaves. Bucky had talked about his parents and his sister, Becca— an Omega and an ex-Army Ranger— and Steve had shared happy stories about his long-gone mother, Sarah. Later, when Bucky had flipped upon hearing that Steve had never before tried baklava, Steve had ordered every piece of the dish that the restaurant had left for the night and they’d eaten themselves into a sugar coma. 

Afterwards they had walked, feeling positively stuffed, a block over to the wine bar that Bucky had been raving about during dinner. After Steve had ordered them a bottle of their oakiest Malbec (which, Bucky had already declared, was his absolute favorite) and tried it for himself, the Alpha had blinked a little in amazement and given the wine two thumbs up. Bucky had chuckled and pointed out that they seemed to share all of the same tastes when it came to food.

_“Maybe we’re Compatible,” he’d half-joked._

_“Ha, yeah.” Steve had replied, rubbing the back of his neck a little nervously. His sudden change in body language was a stark contrast to the easy-going smiles he’d been plying Bucky with the entire evening. “I guess I don’t know much about all that,” Steve admitted. “I mean, I know that they figured out a lot of things about Alpha-Omega pairs after I went into the ice.”_

_“A lot,” Bucky had agreed. They hadn’t talked much yet about the fact that Steve was still sort of a man out of time. “What all do you know about it?”_

_“Well I, uh. I know that it’s not that common to find a Compatible partner.” Bucky had nodded, encouragement for Steve to continue. “But I know that, if you do, the experience can be very different. I know that… Heats are different. And I guess that’s when Alphas can go a little nuts.” _

_Steve had blushed all the way down to his neck as he spoke, which Bucky had found adorable; it reminded him of the old television shows from the 1950s where no one was allowed to say ‘pregnant’. _

_“We call it a rut now,” Bucky had said. He’d made sure to keep his volume level with the rest of his words when he said ‘rut’, showing Steve that it was okay to talk in public about these things in 2016. “And yeah—the Heats are a lot more intense than just regular heats.”_

_Steve had cocked his head at him then, curious.“You sound like you know from experience. Have you ever been with someone Compatible before?” His face had suddenly shifted, mortified. “Oh my god, I’m so sorry— that was so rude. You don’t have to answer that.”_

_“It’s okay,” Bucky had chuckled. “Once, yeah. He was my college boyfriend, actually. We were together for three years. My last stint at anything serious. His name was Erik.”_

_Steve had seemed to consider this for a second as he took a sip of his wine._

_“Why did you and Erik break up? If you don’t mind me asking.”_

_“I don’t mind at all. You can ask anything you want.” He’d given Steve a reassuring smile. “Anyways, with Erik, it was all there biologically, and that part was really great, yeah, but he just… He just wasn’t good for me.”_

_In of the corner of Bucky’s vision Steve had tensed up, which made Bucky wince; he really hadn’t wanted to put a damper on the easy mood of the evening._

_“He didn’t... Tell me he didn’t hurt you, Bucky.”_

_“No!” Bucky had blurted, managing to keep his voice low so as to not draw attention. Steve then visibly relaxed at his response. “It wasn’t like that at all. Erik wasn’t… I mean, he was good to me and everything. He was a sweet guy, actually; he just wasn’t going to be a good partner for me in the long run. When we graduated, I wanted to focus on my career. He wanted to get right into starting a family, and that wasn’t going to work with my plan because I wanted to get on a heat suppressant while I got things started at Stark Industries. Didn’t want that distraction. So I told Erik I needed a partner who wanted to support my goals.” Bucky had shrugged. “It was an amicable split.”_

_Steve had nodded then, understanding._

_“So what about you?” Bucky had asked, changing the subject. “I’m going to infer from the way you’re talking that you’ve never had a Compatible partner.”_

_“Actually, I’ve, uh. I’ve never been with an Omega before.” _

_And Bucky had only _just_ managed to smother the incredulous noise that rose in his throat. As much as he’d found Steve’s admission hard to believe, he could also see that the Alpha had been insecure about it. The perfect, rosy blush that Bucky had come to love so much already tickled Steve’s face and neck, but he didn’t want embarrass Steve further._

_“Gotcha,” Bucky had said instead, trying his best to keep his face neutral. “I hope it’s okay if I ask this, but, um… What about Peggy Carter?”_

_Steve had smiled fondly at the mention, and Bucky had been glad that the memory apparently triggered some measure of comfort for Steve_

_“Pegs was fantastic. I really did love her, might’a married her after the war,” he’d said. “But no, she was a Beta.”_

_Bucky had nodded. “And no one before or after her, I guess?”_

_“None. I sorta dated a couple other Betas after I came out of the ice, but— yeah. None of them were… like you.” Bucky had almost interjected and completed Steve’s sentence, urged him that it was okay to say ‘Omega’, but he stopped himself. All things could evolve in good time. “And before Pegs, well… I wasn’t actually an Alpha before the serum.”_

_But at that, Bucky _hadn’t_ been able to stop himself. “What?! Really? How?”_

_Steve had just shrugged, apparently unfazed by Bucky’s rather rude reaction. “I was born a Beta. It was just a part of Dr. Erskine’s serum. I guess the Alpha hormones were a better fit for the whole super soldier recipe.”_

_“That’s so weird,” Bucky had marveled aloud, genuinely interested in the mechanics of Steve’s transformation. “I mean, not _weird_— I don’t think you’re weird, Steve— it’s just so strange for me to think about what it would feel like to suddenly have my _designation_ change overnight.”_

_“I mean, on the whole, it wasn’t really that weird,” Steve had responded. “I mean, the hundred and forty pounds of body I gained was a lot weirder, was a lot more to get used to. Besides, it doesn’t really feel like a whole lot has changed. People just smell different, now.”_

_“I guess that makes sense,” Bucky had said, considering Steve’s logic. “Thanks for telling me all of that, by the way. It means a lot to me that you trust me with all of those personal details.”_

_Then Steve had flashed him a warm smile that made Bucky melt into his wineglass. _

_“I’m really glad,” Steve had said after awhile of comfortable silence. “What I mean is— I’m glad you chose to pursue your career instead of staying in that relationship. Tony says he thinks you might be the best engineer he’s ever hired, Buck.”_

_“Really? He said that?” Bucky was used to Tony’s cheesy praise in the presence of others, but it meant a lot to him that Iron Man himself would talk about Bucky and his work to others when Bucky wasn’t around._

_“Yeah, he did. I said it didn’t surprise me; I think you’re probably even smarter than he is.”_

_And Bucky had preened. He couldn’t have helped it; he loved it when the Alpha showered him with compliments. _

_He’d watched then as Steve closed his eyes and took a deep inhale._

_“What’s up?” Bucky had asked._

_And Steve’s eyes had fluttered open slowly, and he’d given Bucky a soft, handsome smile._

_“Nothing,” Steve had replied, finally exhaling as he looked back into Bucky’s eyes. “I just really like how you smell when you’re happy.”_

Later that night, Steve had kissed Bucky for the first time against the fire escape outside his apartment building, and Bucky had gone dizzy at all of the combined sensations— the smoothness of Steve’s chapped lips, the hot press of tongue against his, the light scrape of Steve’s beard over his skin, and the scent of happy Alpha in his nose. Steve had a good four inches on him, and Bucky had reveled in the way he’d had to tilt his chin up to capture Steve’s mouth.

_“Goodnight, Stevie,” he had found himself calling as the Alpha walked away and began to mount his bike._

_Steve had turned and grinned back at him._

_“Stevie, huh?_”

_Bucky had been thankful to have the shadow of the fire escape to hide his blush. “Sorry. Can I call you that?”_

_And Steve had laughed, and Bucky had felt warm all over. “As long as you keep letting me call you Buck.”_

_—_

**"Mating Science: A Brief History", ** **Guest Writer Dr. Peter Harlow, M.D. - continued**

After the 1966 revelation of Compatibility, the sharpest minds alive in the second half of the twentieth century turned out to join in on the newest, hottest academic field around: mating science.

Compatibility was a biochemical trait, and pheromones and hormones could be studied under a microscope. New schools of thought cropped up, with some academics supposing that these observable chemical reactions must represent some other unexplained phenomenon, as the evolving sociological study within the field of mating science did not support the conclusion that all Compatible pairs would be physically unable to keep their hands to themselves when the Omega entered a Heat. Furthermore, the frequency of Compatibility observed in laboratory blood tests of Alpha-Omega pairs was inconsistent with the observed traits of Compatibility in the general population. 

Then, in 1981, a French biophysicist named Russeau began to dabble in the world of mating science. With a combination of luck and born brilliance, Russeau soon discovered that Compatibility was much, much more nuanced than previously thought. Compatibility, it turns out, was a _spectrum_ _phenomenon_. 

—

Bucky finished pouring the juice and sat back to admire his work. He hadn’t actually meant to create such a breakfast spread, but replaying the memories of his past two months with Steve had him humming happily and giving into his baser hindbrain desires. Sometimes, he just loved being a doting Omega for his new Alpha— although they hadn’t actually taken to calling each other those terms out loud yet.

He looked at the time and jumped; he had nearly let Steve oversleep. Tucking a strand of hair back into his messy morning man-bun, Bucky strode over the bedroom and kicked aside the towel before entering.

“Time to wake up, baby,” he whispered, crawling into bed beside his boyfriend. 

The larger man stirred and slowly blinked his eyes open.

“_Mmm_… morning, Buck.” Steve grabbed for him and pulled him down for a chaste kiss, apparently wanting to spare Bucky of his morning breath. (Not that Bucky cared, like, at all. Steve Rogers could have a dirty garbage disposal for a mouth as long as he never stopped smelling like a campfire in winter.)

“Morning, Stevie,” he smiled.

“What time is it?”

“Almost eight. Time for you to wake up, sleepy head.”

“Ugh, fine,” he said, faking a dramatic expression. “But _you’re_ the reason I’m tired, you know.” And Steve smiled a little wickedly, pulling him back down. “You’re the one who kept me awake with all of your seductive, evil ways.”

Bucky fell into Steve’s incredible, strong arms and let himself be smothered for just a moment. 

“Sure, alright. My fault you were up late,” he laughed, before lowering his voice and pulling his head up from where it was smushed into Steve’s chest, brushing their noses together. “But my ‘ways’—for good or for evil—certainly didn’t prompt any complaints from you when I had your cock in my mouth.”

His language had it’s intended effect; Steve’s skin instantly lit up in pink everywhere Bucky could see, and the Alpha’s breath hitched a little, but his smirk grew into a grin all the while.

“You’re right, baby doll,” he whispered low, framing Bucky’s face in his broad hands and locking their gazes. Not for the first time in the past twelve hours, Bucky felt his own dick twitch. “No complaints here.”

Bucky was just beginning to work out the math in his head of how they could make morning blowjobs fit in their tight schedule when Steve suddenly bolted up into a sitting position. Bucky immediately let out a laugh.

“Yes, you smell bacon. Dork.” Bucky lifted himself off the bed while he still had the self control to avoid getting both of them into trouble. “Go take a quick shower and come eat.”

Steve flashed a toothy grin and set off to the bathroom to do as he was told.

Bucky returned to the kitchen and set to work pouring two cups of coffee. He heard the shower turn on and thought back to earlier, when he had _really_ wanted to wake up Steve early and pull him into the shower with him. Shower sex was something they hadn’t had a chance to get to just yet.

Well, actually, there was a _lot_ they hadn’t gotten to yet. In fact, they had made it all the way until their fourth (real) date, only two weeks ago, until anything sexual happened between them. The wait was definitely _not_ Bucky’s idea; honestly, the only reason he hadn’t dragged Steve up to his apartment after their first date was because he didn’t want to risk offending Steve’s old-fashioned sensibilities.

On their second date, Bucky had successfully pulled Steve into his apartment at the end of the night, but then he’d pulled out the fixings for Moscow Mules and the two of them had gotten really, really drunk and laughed and made out and— no joke— had a fucking _pillow_ _fight_ before collapsing on the bed and passing out.

Their third date had been a Sunday afternoon picnic in the park, where they had curled up on a blanket and warmed themselves against the slight, crisp chill of autumn air, feeding each other pieces of fruit like something out of a Hallmark movie— before Steve had received a 911 call from the Avengers and the date had ended early out of necessity. Steve had kissed Bucky passionately and apologized, over and over, but Bucky had said that he understood his job could be crazy and promised to always forgive Steve as long as Steve always kissed him like that.

Both of their lives could be pretty crazy at certain times— Steve’s much more so than his, true— but they’d found time in between dates to have lunch and coffee near the Tower. A few times, Steve had snuck into Bucky’s lab when he’d been alone just to bring him chocolates or silly little presents, or to let Bucky win an arm wrestling match. Bucky had returned each and every little favor with an enthusiastic tongue shoved down Steve’s throat.

Then the evening of their fourth date rolled around and Bucky had been determined to make sure that _someone_ got naked. It had been a Saturday, and Bucky had called Steve in the morning to invite him over for dinner that evening. He’d spent the day sprucing up his apartment and gathering ingredients at the store to make vast quantities of his _bunica's_ Radauti soup— his Romanian grandmother’s recipe—before taking awhile to luxuriate in a warm bath and get every inch of his body squeaky clean. Then he’d spent an embarrassing amount of time working on his hair and picking out his best sexy-but-still-comfortable-and-not-trying-too-hard outfit. 

Then the sun had dropped below the horizon and Steve was knocking on his door. Bucky had greeted him with a slow, hot kiss that had clearly gotten Steve’s blood buzzing, before pulling away with a teasing smile and asking Steve about his day. 

Bucky’s master plan for seduction had worked almost perfectly. After dinner, they’d cuddled up on Bucky’s couch and thrown on a movie (which Bucky hadn’t _any_ intention of watching). Bucky had spent the first fifteen minutes of the movie slowly closing each individual gap between their bodies, all the while feigning nonchalance, until one tiny little shift had caused Steve’s nose to come within a centimeter of the scent glands on Bucky’s neck and Steve had let out one hell of _groan_, deep and gravelly and definitely involuntary. Steve had looked embarrassed about his reaction for about two seconds before Bucky was straddling his lap and grinding their excited crotches together.

Five minutes later had found them crashing through the door of Bucky’s bedroom, attached at the mouth, hands all over everywhere. Bucky had gotten Steve down to his sexy boxer briefs (which did _nothing_ to hide the Alpha’s legitimately terrifying size, Bucky had noted) and Steve had just removed Bucky’s last article of clothing and urged him down onto the mattress, when the bigger man had suddenly stopped. 

_“Something wrong, Stevie?” Bucky had asked, looking up at the mountain of an Alpha in front of him. _

_Steve had been tall and towering above him from his position on the bed, impossibly broad chest and shoulders that tapered down to his fit waist, and trunk-like thighs that had looked to Bucky to be thicker than the Omega’s own abdomen._

_“Nothing’s wrong,” Steve had replied, and Bucky hadn’t missed the sudden shakiness in his voice. “I’ve— just. I’ve told you that I’ve never been with an Omega before, right?”_

_And Bucky had wanted to pull Steve into his lap and soothe him, but to also climb him like a fucking _tree_._

_“Nothing wrong with that,” was where Bucky had settled. “I know you’ve been with Beta men, though. You okay with trying something a little different tonight? We don’t have to do anything you’re not comfortable with yet.”_

_“Yes,” Steve had breathed, voice full of wanting. He’d moved to settle his body on bed beside Bucky, and Bucky had leaned into him to press a tender kiss against his mouth. “Please. I wanna feel you, Buck.”_

_“Feel all you want, baby. I promise I’ll make tonight worth your while.”_

_Bucky had made it to third base with plenty of other guys before, Alphas and Betas, but for some reason Steve had felt different that night— so different and so, so much better, like there had been moonlight and magic shooting from Steve’s fingertips and straight into Bucky’s skin. Steve had asked him to lay back on the bed and Bucky had complied happily (and maybe a little too enthusiastically), stretching his arms above his head while the Alpha let his hands wander. Under Steve’s ministrations Bucky had gotten fully, painfully hard in minutes._

_“Can I touch you?” Steve had whispered against his mouth, hand resting gently and patiently against Bucky’s inner thigh._

_Bucky had given Steve a happy little sigh and spread his legs. He’d felt open and vulnerable laying there on the bed for Steve, but the feeling had made his body sing with delight. He’d even found himself subconsciously leaning his head back to reveal the expanse of his neck, an instinctive and clear expression of an Omega’s trust and submission to an Alpha. Steve had moaned low and appreciatively in response._

_The blond had let go of Bucky’s mouth to place a wet kiss against his right nipple before moving lower, mouth hovering with hot, humid breaths over Bucky’s dick— comparatively smallish, like most Omegas, but Bucky was rather proud its girth nonetheless— before pulling away. That had been when Bucky’d realized that Steve Rogers was _not _as innocent as he came off; he was _definitely_ an egregious fucking tease._

_But Bucky’s annoyance hadn’t lasted long, because then Steve’s patient hand had moved up and a finger began to press, just lightly, into the soft give of Bucky’s body._

_“Fuck,” Steve had cursed, equal parts arousal and wonderment. “You’re _wet _for me.” _

_And Bucky had moaned and then chuckled, sitting up on his elbows to look down at Steve between his legs. “Pretty nice built-in feature, huh?”_

_“God, yes. You’re so fucking hot, Buck. So fucking gorgeous."_

(In the kitchen, Bucky dropped a spoon at the memory. He really did love it when Steve showed off his dirty mouth.)

_“Maybe someday down the road I’ll let you see how wet I can get when I’m in heat,” he’d returned, waggling his eyebrows._

_The idea of Bucky in heat had seemed to break something inside Steve, who’d let out an incredible hot, growly moan. Within seconds he’d pulled back and urged Bucky’s hips up, and Bucky had instantly complied so that Steve could shove two pillows underneath his hips before encouraging him to settle back down and relax._

_“So beautiful, Buck.”_

_Bucky had smiled back at him and Steve had made a happy sound, settling back between Bucky’s legs, face close enough that Bucky had felt warm breaths teasing his balls. He’d placed one finger against Bucky’s entrance, which had just started to really leak slick, and paused, as though awaiting approval._

_So Bucky had given his approval in the form of pushing his ass down, trying to breach himself on Steve’s finger, and loosing a needy whine._

_“Please?”_

_And then Steve had given him a quiet little laugh and pressed in, just to the first knuckle, and Bucky had really thought that the feeling alone might make him come untouched. _

_Steve Rogers was lightning in Bucky’s veins._

Now, in the kitchen on a Monday morning, Bucky busied himself with cleaning a few dishes while Steve finished in the shower. As he worked he had to will himself not to get hard just thinking about that first night they had spent with bare skin pressed against the other’s. 

He still remembered everything about it: the way Steve had quickly found his confidence and fingered him into oblivion, the way he had toyed and played and experimented with Bucky’s body like he was trying to see just _how_ wet an Omega could get, the way he had leaned down and taken Bucky’s dick into his mouth (_“Fuck, Steve, you really _are_ a keeper”_) and swallowed his come each time he came, easy. Bucky felt a little echo of disappointment and regret when he thought about afterwards, when Steve had wrapped Bucky’s loose, languid body up in blankets, insisting that he was perfectly happy already and could do without his own relief for tonight. Bucky had sighed sleepily in surrender, but vowed inwardly to swallow down Steve’s cock first thing in the morning, before the Alpha even woke—but, then, a four a.m. phone call from motherfucking Nick Fury had pulled Steve out of Bucky’s bed and away to South America for one long, awful week.

—

**"Mating Science: A Brief History", ** **Guest Writer Dr. Peter Harlow, M.D. - continued**

The concept of the Compatibility Spectrum finally explained the dichotomy between the laboratory test for Compatibility and the actual observed frequency of phenotypic Compatible pairs in the population. _All_ Compatible pairs would test positive for the trait in a laboratory setting; however, since the expression of Compatibility depended largely on the interactions between the unique hormones in each Alpha and Omega, pairs on different ends of the Spectrum could present in drastically different ways. 

On one end of the Spectrum, pairs that exhibited a low degree Compatibility would experience an exaggerated but reasonably comfortable libido in and around the Omega’s Heat. The Alpha in the pair would typically also exhibit increased territorial behavior concerning the Omega, especially during Heats, but may not always enter a rut. Both members of the pair tend to report a heightened sensitivity to their partner’s scent.

On the far end of the Spectrum, pairs that exhibited a very high Compatibility score were often described as chaotic and sometimes uncontrollable while the Omega was in Heat. Russeau’s laboratory observation of highly Compatible pairs found that the normal hierarchy of needs quickly became unstable in a Heat-rut episode. Omegas in Heat would set aside all feelings of thirst, hunger, and physical comfort in favor of breeding; fortunately, the dramatic crash-and-burn cycles of rut allowed Alphas moments of clarity in which they would instinctively gather vital supplies and obsessively tend to their mates. Upon consummating the relationship with the first knotting, most Alphas in highly Compatible pairs would report an enhanced urge to bite; however, the biting instinct reportedly became comparatively manageable in all ruts after the first (although still present, sometimes to the degree of pain), and the drive would disappear altogether if a mating bond was completed. 

It is now understood that the historical occurrence of highly Compatible pairs in society explains the sensationalist anecdotes that once sunk so deeply into the public understanding of mating behavior; however, studies suggest that highly Compatible pairs account for less than 1.5% of all Alpha-Omega pairs globally.

—

Bucky’s thoughts were temporarily drawn away from dirty places by the sound of the shower turning off. The respite didn’t last long. He found himself conjuring a fantasy mental image of his boyfriend stepping out the shower, what that might look like: tan, naked skin, little water droplets falling out of his hair and down onto his laser-cut hips, his thighs, his _massive_—

But of course _that_ thought sent Bucky’s brain deep, deep back into the gutter, and he found himself mentally recounting the events of just the _previous_ night, here in this apartment, when he had finally gotten Steve back into his bed without so much as a scrap of clothing to hide him from Bucky’s hungry eyes.

_“Jesus fuck, Steve.”_

_Bucky had just finished removing Steve’s jeans and underwear, both articles shoved down past knees and ankles a with single, efficient push of Bucky’s hands, and then the Alpha had been exquisitely and fantastically bare in front of him, a feast for Bucky’s eyes from where he’d been kneeling on the bedroom floor._

_“Um, yeah,” Steve had chuckled above him, a little nervous and a lot adorable. “Serum kinda made _everything_ a little big, I guess?”_

_And, oh, Bucky had _felt_ before though boxer briefs that Steve must have clearly fallen into the well-above-average category, even for an Alpha—but ‘a little big’ was _not _the way Bucky would have ever described the mouth-watering specimen in front of him. _

_Sitting there, jaw hanging open and dumb expression on his face, Bucky’s brain had carded through the spinning wheel of thesaurus terms in his brain: ‘colossal, gargantuan, humongous, mammoth, titanic’. But then he’d noticed Steve shuffling his feet a little, and _to hell_ if Bucky was going to let Steve feel insecure about the single most amazing creation of human flesh that had ever existed. He’d forced the cockstruck look off of his face in order to rise to capture Steve’s mouth in a heated kiss._

_“You are incredible, Steve. And now, I am going to suck your dick hard enough to make you pass out.”_

Bucky could hear the sounds of post-shower Steve shuffling around in his bedroom, no doubt looking for his strewn clothes. He set the coffee mugs down on the table and took a seat.

He couldn’t help the grin that now covered his face as he thought back to the sounds Steve had made when Bucky had first sat him down on the edge of the bed and taken him into his mouth, as _far_ as he could get— which, as it turned out, was less than halfway. If Bucky were being honest, he’d really had every intention of getting Steve inside of him last night. But, once he’d considered that Steve’s experience with penetrative sex (at least as an Alpha) may have been little to none, he’d placed that particular priority on the back burner and set out to make Steve see stars.

It had occurred to Bucky a few days prior (alone in his bed with his own hand curled around his dick, vibrator snug inside him) that since Steve had never been with an Omega before, that meant that he had _never popped a knot_. Alpha-Beta pairings (and, more acceptably in the last several decades, Alpha-Alpha pairings) worked just fine, a million different types of pleasure enough to go around for everyone, but the presence of an Omega was a biological necessity for an Alpha’s knot to expand.

And so last night, as Bucky had sat back on his knees and worshipped Steve’s gorgeous, _thick_ cock— nearly thick enough to split the skin around the corners of Bucky’s mouth as he worked— he’d used his hands and mouth to bring Steve near the precipice before posing his question.

_“You ready to pop your knot for me, Alpha?”_

_And Steve had positively _howled _at the comment, like someone had shot him through with electricity. He’d immediately began thrusting up into Bucky’s fist and coming, buckets, _everywhere_, falling onto Bucky’s lips and hair and sheets, running in rivulets down his fist and forearm. As soon as it had started Bucky had moved both of his hands— as the issue of circumference had demanded _two_ hands— down to wrap around the base of Steve’s cock and _squeezed_. _

_Steve’s knot had quickly filled with blood and widened, so _wide_, and Bucky had made sure to increase pressure slowly as it expanded. It had been a pretty damn good simulation of the pressure an Omega’s body would create, if Steve’s continued thrusting and awed, erotic noises were any indicator, but eventually the knot did deflate. Bucky had thought longingly to a day in the (hopefully very near) future when he would have Steve inside him and the knot would _last_— ten, twenty, maybe even thirty minutes— tying them together and filling him up._

_After the knot had deflated (although the rest of the erection, Bucky had noted, had bizarrely _not_ flagged), Bucky had retrieved a towel from the bathroom and cleaned them up. Then Steve had pulled Bucky down onto the bed and taken him into mouth, fingering him and teasing the rim with his tongue before bringing him to a total state of nirvana._

_“Thank you, Buck,” Steve had whispered in his ear as they drifted to sleep afterwards. “I pretty sure I’m the luckiest guy in the world.”_

_“Nah.” He’d turned his head around then to give Steve a smile and a little wink. “That would be me.”_

“What’s on your mind, gorgeous?”

The sudden presence of Steve’s voice in the kitchen jolted Bucky from his thoughts. He shook his head and recovered quickly, shooting Steve a look and a wry smile.

“Oh, nothing. Just thinking about how pretty you look when you’re coming all over my hands.”

Bucky was thankful for the fact that Steve was still topless— a sinful specimen of classic handsomeness, walking in with an understated quaff to his hair and wearing nothing but his denims— because it meant he got to better witness the fantastic full-body blush that came over Steve whenever Bucky said something particularly dirty.

“Uh, yeah. Glad you liked it,” Steve laughed as he sat down and grabbed the mug Bucky had set out for him. “You cooked me breakfast, Buck?”

“Yep. With enough protein and starch for a super soldier. Now eat up, babe.” Bucky reached over to grab a piece of toast for himself. “You gotta get out of here soon if you’re gonna be on time for your flight.”

Steve gave a small moan of disappointment at Bucky’s mention of his upcoming trip. The Alpha was going to D.C. for a few days with some of the other Avengers, apparently to do some (reportedly bullshit) safety demonstrations for the Defense Department.

“Gonna miss you,” Steve said, a little sadly, between bites. As he took a sip of his orange juice he gave Bucky a sweet, self-conscious smile. “I, uh. I kinda can’t believe some of things you did for me last night.” He reached up and rubbed the back of his neck. “I didn’t even know my body could _do_ some of those things.”

Bucky grinned and leaned forward to give Steve a peck on the cheek. He stayed there afterwards, mouth next to Steve’s ear, and let his voice drop low.

“Maybe _next_ time you could do some of those things inside me.”

Steve choked and spit out his orange juice. 

—

**"Mating Science: A Brief History", ** **Guest Writer Dr. Peter Harlow, M.D. - concluded**

After thousands of hours of laboratory observation, Russeau eventually developed a mathematical model in 1987 in attempt to predict where an Alpha-Omega pair might fall on the Compatibility Spectrum and how the effects would manifest physically. The model tested more than sixty components, but the most controversial component was aimed at predicting the influence of age difference between the individuals in a Compatible pair. Russeau had attempted to model this effect after observing that the most highly Compatible pairs in her studies included Alphas that were at least seven years older than the Omega. Sadly, Russeau passed away in 1990 before her models could be tested in a controlled study. 

Years passed, and by the turn of the century the study of mating science had fallen out of popularity in the academic community, replaced by pharmaceutical interest in controlling heats and developing products that could block scent. Nonetheless, the contributions of mating scientists in the twentieth century had supplied invaluable information that forever changed the lives of real people.

Erica Russeau, a Beta female, was awarded the Nobel Prize in Medicine posthumously in 1992.

—

“Don’t want you to _go_,” Bucky whined, watching Steve collect his shoes from the living room. 

“I know.” Steve gave him a sad smile as he picked up his duffel. “I never wanna leave you, Buck. Always feels wrong somehow.” 

Steve pulled Bucky into a full body hug, dwarfing the smaller man with his frame. Bucky pouted but went anyway. 

“When do I get to see you again?” Bucky asked into the fold of Steve’s underarm. He tried his best to hide the weird way he liked to scent the Alpha there. 

“Saturday, maybe Friday if we’re lucky.”

“Ugh. Fine. Call me and text me?”

“All the time, baby.”

“And don’t leave me for someone cuter?”

Steve’s muscular chest vibrated against Bucky with Steve’s deep laugh. “Impossible, there’s no one cuter.”

“Okay. Bring me back a surprise from D.C.?”

“How about the nuclear football?”

“I will accept it.”

He leaned his face up to catch Steve’s lips in a kiss. It sent a tingle down Bucky’s spine and made the hair on the back of his neck stand out straight. 

“Goodbye, beautiful,” Steve whispered as he pulled back from the kiss. He brought a hand up to Bucky’s face and brushed his inner wrist over Bucky’s neck on the way up, and Bucky didn’t miss the Alpha’s sweet, less-than-subtle move to scent mark him. 

“Goodbye, Stevie.”

Bucky watched down the hallway as Steve walked away. 


	3. Act II - Rising Action

**Summary for the Chapter:**

> Steve and Bucky discuss how to handle Bucky's impending Heat.

**Notes for the Chapter:**

> No content warnings apply for this chapter.

**Act II - Rising Action**

\---

Bucky Barnes woke up feeling like absolute _shit_.

His head hurt, his muscles ached, and he was clammy all over. 

And, _god_, he missed Steve.

Today was the fourth day that Steve had been gone in D.C. He had texted and called Bucky almost every chance he got during his busy schedule, but Bucky still missed him like crazy.

He reached for the nightstand and grabbed his cell phone.

“_Stevieeee_,” Bucky whined into the phone. He had called Steve mostly to complain, but also to hear his voice. “I’m _siiiiiick_!”

He didn’t care that he sounded like a complete baby; he felt like absolute garbage and he wanted Steve to make him feel better— somehow.

“What’s wrong, baby?” Bucky could hear the concern in Steve’s voice, as well as some background noise that sounded to Bucky like Tony bickering with someone about lunch options. “Do you need to see a doctor?”

“Ugh,” Bucky mumbled. “Probably. But I don’t wanna, Steve. My GP is all the way on the other side of town and I don’t feel like dealing with the trains today.” Then he tried lowering his voice to what was probably a horrible attempt at a seductive tone, given the nasal quality of his voice today. “Want you to make it all _better_, baby.”

“Get out of bed and get dressed.” Steve’s voice was firm, like an order (which, okay, excited Bucky’s dick maybe a _little_). In the back of his brain Bucky was kind of impressed that Steve had correctly assumed Bucky was still in pajamas at ten past noon. “Tony’s people will send a car.” 

_“They will?” _Bucky heard Tony say in the background. Steve said something incoherent and far away from the receiver. _“Oh, yep—sure thing, Cap. Whatever Bucky boy needs. Gotta keep our genius in tip-top shape. Tell the kid they’ll be there in fifteen, okay?.”_

“Hear that, Buck?” came Steve’s voice again. “Fifteen minutes.” Bucky sighed to himself and allowed his clammy skin to be warmed by the way he felt when Steve Rogers took care of him. “Now, go get dressed. One of our meetings just got cancelled and I get to come home tonight; I don’t want you feeling miserable when I see you.”

“Mmm,” Bucky hummed, over-the-moon happy to hear Steve’s news. He _needed_ to see his boyfriend. “I can’t wait. Miss you so much.”

“I miss you, too, Buck.” Steve kept his voice low, like he was telling a secret for only Bucky to hear. “So much. Can I come over tonight? I’ll bring you soup.”

The thought made Bucky smile. “Eight o’clock,” he said. “If you’re back in town by then.” 

“I will be. Buck?”

“Yeah?”

But then Steve paused, saying nothing more for several seconds.

“Nothing,” he said after awhile. “I’m just excited to see you again. See you at eight, baby.”

—

“Bucky, I’m going to recommend that we deactivate your suppressant for awhile.”

Bucky just stared at Dr. Pete, blankly. His dorky, middle-aged GP set down his chart, which was filled with the results from all of the lab tests Bucky had submitted to an hour earlier.

“What,” he deadpanned in response.

“You’re feeling sick because your body is reacting to a hormone deficiency. In Omega males, these are typically caused by long-term use of a suppressant and changes to certain external stimuli. My recommendation is that we turn off your suppressant until you have a heat. After that, we can turn it back on, at least for a while.”

Buck looked down at his right arm, where his dual purpose suppressant/birth control implant was faintly visible under the translucent skin of his inner arm. He didn’t know everything about how it worked, but he knew it contained two separate components that could be individually activated or deactivated via a specialized medically-designed magnet.

“You’re saying I’m feeling like this because I need to have a heat?”

“That’s correct.”

Bucky’s head swam, whether from the information he was still trying to process or the incessant pounding in his brain.

_Ugh. Make it go away._

“Why now?” he asked, confused. “And why me? I’ve never heard of other Omegas having this issue before.” It was true; he’d never heard of such a problem.

“Bucky, have you recently been spending a lot of time around a new Alpha? Maybe a new partner?”

The question took Bucky aback a little, but he nodded. “Uh, yeah, actually. My new boyfriend and I met about eight weeks ago.”

Dr. Pete nodded like he had expected this information. “Then I suspect that you and your boyfriend may be Compatible, Bucky.”

“_Compatible_?” Bucky repeated in shock. “What— how does that have anything to do with my suppressant?”

“Well, you’re not wrong that these reactions don’t happen often; in fact, they are exceedingly rare. But, when they do, it is my experience that they are usually a reaction to the presence of a highly Compatible Alpha.” Bucky’s eyebrows rose even further at Dr. Pete’s use of ‘_highly_’. “I take it you and your new boyfriend haven’t taken a home test?”

Bucky had only taken a Compatibility home test once in his life, with Erik, a few months into their relationship and about a month before he’d been expecting a heat. He’d bought it in a drug store and taken it back to his dorm, where he and Erik had pricked their fingers onto little blood strips and waited, five minutes, before Bucky had read out the results: Compatibility positive, ten to twenty percent. His impending heat was to be a _Heat_.

Bucky shook his head in response to Dr. Pete’s question. “No, we haven’t. We had kind of talked about it in passing a couple of times, but not seriously.”

“I understand. The use of these tests has decreased as the popularity of suppressants has increased. The Compatibility status isn’t typically as important to couples that don’t experience heats together.”

Bucky nodded. Having experienced the pleasure of a Heat with a Compatible Alpha before, Bucky couldn’t deny that he had wondered if he and Steve could have that together some day. But right now it seemed like everything was still too new, and there would be plenty of time for that down the road.

“Here’s what I recommend,” Dr. Pete continued. “First, we should deactivate your suppressant; I can do that here in the office today. You can then expect to have a heat in three to six months. After that, you can return and we’ll switch the suppressant back on, and you can return to life as normal unless this happens again. There’s no need to deactivate the birth control hormone cartridge, since I don’t believe it’s causing any adverse reactions right now.”

Bucky nodded. He could deal with having a heat three to six months from now. That gave him plenty of time to talk to Steve about how it might affect them as a couple.

“The second thing I’ll do is give you a supplement shot today. It will help your body clear out the effects of the suppressant faster, and you’ll be feeling symptom-free by tomorrow morning.” 

“Okay,” Bucky agreed. He liked that part. “That sounds good.” 

“And the last thing,” Dr. Pete continued, “is that I’m going to send you home with a Compatibility home test today.”

“Oh… okay.”

“It’s entirely up to you and your boyfriend as to whether you take it. But I’m going to recommend that you consider it, Bucky. Even more so than the average Compatible couple, Heats for highly Compatible couples can be very intense. I think it’s best that you know what you’re in for, if you want to spend it together.” Bucky understood the logic, even if it was a lot to comprehend. “The test kit I’m going to give you isn’t nearly as precise as a lab test, but it will still give you important information. In addition to providing a positive/negative result, it will classify positive results by range of Compatibility. This way, if you’re Compatible, you will know approximately where you lie on the Spectrum and what to expect.” 

Bucky exhaled. His head was pounding and he still felt like shit, but what Dr. Pete was saying was a lot to consider. It excited Bucky; he couldn’t deny it. But he needed to talk to Steve. 

“Okay,” Bucky said. “Let’s turn off the suppressant and do that shot. I’ll… I’ll talk my boyfriend about everything else.”

Dr. Pete nodded. “I think you’re making the right decision, Bucky. I’ll have my nurse come back in a moment with the supplies we need. If you do decide to take the test and you find out that you’re highly Compatible, I suggest giving me a call at your convenience and we’ll discuss some of the exaggerated effects you might experience together in a Heat.”

Bucky nodded, and Dr. Pete left the room.

He had a lot to think about before eight o’clock.

—

Bucky stepped out on the street and pulled out his cell phone. He swiped open to his favorites and tapped on Steve’s name.

“Hey baby,” the Alpha’s voice greeted. “How you feeling?”

“Uh, actually, pretty okay now.” It was the truth; he had only gotten the supplement shot thirty minutes ago, but Bucky was already starting to feel the ache in his skull subside. “The doc was really helpful. I’m glad I came.”

“That’s great!” Steve enthused. Bucky loved the way Steve sounded when Bucky was letting him take care of him. “Just sit tight, Tony’s going to call to have that car come around.”

“Thanks, Stevie. I really appreciate you looking out for me.”

“Of course, anything for my best guy. What was the problem, anyways? I hope not the flu.”

“Nothing like that,” Bucky said. “Just… hormone stuff. I’ll tell you all about it later.” He looked down at his loose shoelace, fidgeting a little. “Actually, I need to talk to you about some stuff when you come over tonight, okay?”

“Sure, baby.” Bucky didn’t miss the hint of wariness in his voice. “Is everything…" 

“Everything’s great, babe,” Bucky reassured. “It’s a good kind of talk.” _I think_.

“Great,” Steve replied, perking up. “See you at eight, beautiful. I’m bringing my pj’s." 

Bucky smiled. 

“You’d better.”

—

By the time eight o’clock rolled around, Bucky had showered and changed into a fresh pair of sweatpants and a t-shirt. The supplement shot had been everything that was promised and more; his head was feeling clear and the weird, uncomfortable sweating had stopped. In fact, he was just thinking he was starting to feel pretty darn fantastic when the buzzer rang and Bucky clicked to let Steve up.

The big, blond Alpha soon came bounding through the door like a golden retriever, if golden retrievers could carry several gallons of chicken noodle soup in their arms. “Hey, baby!” 

Bucky couldn’t stop the manic grin that split his face. “Hey, Stevie.” 

Steve set down the soup containers and scooped Bucky into his arms, lifting him off the floor and spinning him around like a dame in the movies. Bucky let out an easy laugh.

“God, I missed you so much,” Steve mumbled into Bucky’s neck as he set him down, holding their bodies close together with two hands on Bucky’s lower back. When the Alpha pressed his nose into Bucky’s scent glands and inhaled deeply, Bucky noticed that Steve stayed there a good amount longer than he normally did. “Mm. You smell _extra_ amazing today. You doing something different?”

“Um.” The gears took a moment to turn in Bucky’s floaty, lovestruck brain as he thought about the supplement shot and the deactivation of the suppressant cartridge. “Maybe? Might have been the medicine the doctor gave me today.”

“That stuff got you feeling better?”

“Yeah,” he said. “Lots. Told you I’d be all ready for you to come home and kiss me.”

“That you are,” Steve grinned, before leaning down and covering Bucky’s lips with his own.

And Bucky had let out a happy sigh and melted into it. 

After that, Bucky grabbed a couple of bowls and spoons and a ladle, Steve picked up some crackers out of the pantry, and they parked themselves on Bucky's couch with too much soup and a lot of lost time to make up.

Bucky listened as Steve recounted some of the more interesting aspects of his D.C. trip— and some of the less interesting ones— and Steve in turn listened as Bucky caught him up on one or two developments going on with his projects (and also a complete recap of his Community binge re-watch). When they were done they collected the bowls and threw them in the dishwasher before collapsing together on the couch. 

“So what was it you wanted to talk to me about, Buck?”

Bucky swallowed and took a breath, then continued on to recount to Steve all of the things Dr. Pete had told him: the rare reaction to his suppressant, the recommendation that he go through a natural heat, the possibility of their Compatibility, the implications for them as a couple. Steve listened intently the entire time, stopping him occasionally to ask questions and once to read the home test box that Bucky had pulled out when he arrived at that part of the story.

“So, let me make sure I understand. You’re going to go through a heat— of some kind— in three to six months?”

Bucky nodded. “Yeah. Could be a regular heat, but Dr. Pete says that it’s more likely to be— you know— a _Heat_.”

“Right. But we won’t know which kind unless we take this test. And if we don’t know, it could… take us by surprise.”

Bucky glanced down at his fingers and toyed with the loose thread on the blanket covering their legs.

“Do you want to?” he asked, small, a little anxious about the answer. “It’s okay if you don’t want to. I won’t be mad or anything.”

He watched Steve sigh and card his fingers through his hair, thinking. Bucky couldn’t help but admire the way the Alpha’s brows knitted together when he was deep in thought. That, and he found himself relieved that to see that Steve was considering each of his options seriously.

“I won’t lie to you, Buck,” Steve said, moving a hand up to brush Bucky’s hair out of his face. “And maybe it’s dumb of me to be thinking this, but I know you’ve been in a Compatible relationship before, and… I’m just worried how you’ll feel if we take this test and learn that you and I _can’t_ have that together.”

Bucky’s heart about split in two to hear the insecurity in Steve’s voice, to hear that Steve could ever think he’d be second to his ex— or any other Alpha on the planet. He leaned forward and put his hands on either side of Steve’s face. 

“Stevie,” he started, closing his eyes and pressing a firm kiss the side of Steve’s mouth before pulling back, looking the Alpha in the eyes. “Compatible or not, I’m always gonna want you. You got know that, baby.”

Steve blinked a couple of times and then gave Bucky a soft smile. Bucky let himself be pulled in to a long, sensual kiss, filled with promises and something else that he couldn’t quite put his finger on.

“Let’s do it,” Steve said when they parted. 

“You’re absolutely sure? Because we could just wait and see what happens with my heat, you know. Probably not advisable, but—”

Steve just pulled him in and silenced him with another kiss.

—

Bucky sat at the kitchen table, Steve next to him, their hands joined tightly together and resting atop the table. They each sported a tiny little bandage on the tips of their index fingers.

While they waited for their test to process, Bucky tried to keep his mind from racing in the million different directions it wanted to run to. He tried counting the freckles on Steve’s nose instead, reaching his unoccupied hand up to scratch at the itch under his own collar. His skin had been starting to feel weird and prickly over the last hour or so, since about the time Steve had arrived. He chalked it up to nerves. 

The timer on Bucky’s phone went off and the two men looked at each other. Steve grabbed for the test strip reader.

“Look at it together?” 

Bucky nodded. Steve set the reader down next to their joined hands and pressed the read button.

He squeezed Bucky’s hand as they read it.

** _ COMPATIBILITY +_ **

** _SPECTRUM LOC.: OUT OF RANGE_**

“Out of range?” Bucky read aloud, confused. This hadn’t been anything like the numeric result he’d seen when he and Erik had taken the same test. “What does that even mean?”

Steve reached for the test box packaging and began to read the instructions on the back.

“It says that the test can classify ninety-five percent of Compatibility positive couples into one of six readable ranges: one to ten percent, ten to twenty… so on to the last one, fifty to sixty percent. Anything over sixty percent will report as ‘out of range.” He set the box down and looked at Bucky, his uncertain expression underlain with a clear hint of excitement, however cautious. “So you and I, we’re…”

“Compatible, yeah,” Bucky finished for him, smiling and suddenly feeling like he was leaking sunshine out of his pores. “Like, _really_ Compatible, like— like _ninety-fifth percentile _Compatible, Stevie!”

And then Steve let out a warm, whole-body laugh that echoed against the tile of the kitchen. He stood up and surprised Bucky by scooping him into his strong arms,planting a kiss on his forehead.

“Of course we are,” Steve said. When he looked down at Bucky, he was the picture of hope and happiness. His voice got quiet. “With something that feels this special, I don’t know what else we could be.”

Bucky smiled big and pulled Steve down for a deep kiss, holding him there for a moment before parting and leading them both over to the couch. He happily situated himself in Steve’s warm lap and continued to let the buzz of happy ring through his bones.

“So you’re going to, uh-- you’ll spend my Heat with me, when it happens?” He stopped himself from mentioning that if Steve _didn’t_ help him through his Heat, as his Compatible Alpha, the whole thing might end with Bucky peeling his own skin off. At least, that’s what he’d heard before on the internet about highly Compatible couples.

Steve grinned. “I’d love to, Buck. I can’t wait.” He squeezed his hands where they were resting around Bucky’s waist. “I mean, there’s a lot of stuff I don’t know yet, things I should probably learn. You said we can talk to your doctor about what to expect, right?” 

“Sure,” Bucky replied. It was definitely not a bad idea. “I can give his office a call tomorrow and set something up for next week. I think it’ll be good if we do that, especially since you haven’t been in a rut before.”

Steve’s entire expression changed then, and Bucky recognized the look of concern and uncertainty. He realized that they had been talking all evening about the possibility of Bucky entering a Heat, but hadn’t discussed the twin effect of Steve entering rut. Most Alphas never had to worry about it.

“If I— go into a rut, won’t that make me…” Steve trailed off, the faintest hint of a blush appearing on his cheeks. Bucky had to bite his lip to stop himself from making a joke about Steve’s continued old-fashioned prudishness when it came to discussing certain matters of their designations.

“_Feral_?” Bucky finished for him. Steve nodded. “Nah. I don’t think that ever really happens to anyone; it’s just old stories from before the science had figured all this stuff out. I mean, if we’re really _this_ Compatible then I’m sure your rut will be more intense than if we weren’t—but you’ll still be you, Stevie.”

Steve looked relieved. 

“And you really want this, Buck?”

"Yeah, Stevie,” he smiled, placing his hand over Steve’s larger one in their laps. “I really do.”

“Good. Okay.” Steve returned his smile. “And it’ll feel good? For, for—”

“Oh, you have no _idea_, baby,” Bucky cut in. He suddenly felt a little frisky and ground down a little, just a tease, into Steve’s lap. “It’ll feel amazing for both us. Remember the way it felt when I sucked your cock and you popped a knot in my fist, baby?”

Steve let out a choked laugh, clearly a little shocked by Bucky's sudden crass language. “How could I ever forget?”

“Right,” Bucky continued. He placed a flirtatious kiss against Steve’s temple. “Well, it’ll feel like that times a hundred—no, a _thousand_. The more Compatible we are, the better it is.”

“But you’ll like it, too, right?” Steve pressed.

Bucky felt the butterflies returning to his stomach (and maybe tickling his dick) at the tone of concern and— dare he say—protectiveness in Steve’s voice.

“Look, I won’t hide it from you; most of the sex I’ve had with Alphas has been outside of things like Heats, but, well.” He let his fingertips wander as he spoke and began playing with the baby-fine hairs at the nape of Steve’s neck. “Erik and I _were_ Compatible— I mean, not nearly as much as you and I, but still— and my Heats with him were definitely something. I can’t deny it.”

He watched Steve wiggle in place a little uncomfortably, his normally blazing skin heating up even more with something that looked to Bucky a lot like jealousy. Bucky grabbed Steve’s hand and pulled it up to his mouth, taking his time placing little kisses at each knuckle while he waited on Steve to make eye contact with him.

“And you know what, baby?” Bucky asked, looking down at Steve through his eyelashes. “None of that is _ever_ going to compare to what it’ll be like for you and me.” 

Hearing Bucky’s promise, Steve’s face melted back into a happy smile. Bucky brushed his thumb over the handsome crow’s feet at the corner of his eyes.

That night they fell asleep on Bucky's couch, warm and safe and together and feeling ready for whatever the future wanted to throw their way.

—

**Notes for the Chapter:**

> Alright, if you're here because you read the tags and had to pour yourself a glass of ice water... the next chapter is what you came for. Thanks for reading this far-- you will be rewarded handsomely.


	4. Act III - Climax

**Summary for the Chapter:**

> Bucky’s Heat comes early.

**Notes for the Chapter:**

> This chapter is the where this entire story started for me, the PWP one-shot I attempted to write before it wiggled its way out of my grasp. It is 10k+ words of pure, unadulterated filth. Thank you to everyone who read this far; here is your reward.
> 
> CONTENT WARNING: First, the sex in this chapter is overall caring and enthusiastic on the part of both participants in an established sexual relationship. However, certain sections contain elements of dubious consent and possibly non-consent due to an entirely fictional biological imperative that is not present in the real world. If you are sensitive to (or not interested in reading) work with these themes, please inform your decision to read further by visiting the A/N at the end of the chapter now (slight spoilers).

**Act III - Climax**

\---

Bucky Barnes woke up with his skin on fire and a massive erection pressing against his ass.

After that, the next thing he noticed was the scent— oh, god, _Steve’s_ scent. It wasn’t just swirling lightly around him anymore, it was _filling_ the room like some sort of erotic hot box. And it was different, not just stronger but sharper, more bold and aggressive; if Steve had smelled like campfire and bergamot before, now he smelled like someone had set fire to a goddamn cedar forest and then tried to douse it out with over-steeped tea.

But oh— _fuck_— how Bucky wanted to throw his body in and burn _with_ it.

Bucky was entirely unfamiliar with the duality of arousal and sheer panic that gripped him now. The thick, hard cock at his back was grinding into him, its owner’s arms wrapped tight around Bucky as Steve slept, and it was all Bucky could do to bite back a wanton moan.

_Oh_, and his ass was very freely leaking slick.

In his mind, instinctively, Bucky knew what has happening— he didn’t understand it, the _how_ of it all, but that didn’t change the fact that it was _definitely_ happening.

He was in Heat, and Steve— Bucky’s very, _very_ CompatibleAlpha— had entered a rut right alongside him.

Bucky pulled together every fiber of control he had left in his body to try and cool his brain, to think about what to do next.

_Baby steps_, he told himself. _One thing at a time._

His phone. He needed to get his phone and call Dr. Pete. Daringly (and probably stupidly, given the high potential for a nasty reaction), Bucky began an attempt to extract himself from Steve’s arms. Amazingly, it worked; after some careful maneuvering that made him feel like he was dodging laser sensors in a heist movie, Bucky finally got himself upright and off the couch.

He ran to grab his phone off the counter and silently stepped into the bedroom, closing the door behind him. He ran through the contacts in his phone until he found the office number for Dr. Pete.

“_Hello_,” a voice recording answered. _“You have reached the office of Dr. Peter Harlow. We are currently outside of normal business hours. If this is an emergency, please hang up and dial nine one one_—”

“Fuck!” Bucky cursed under his breath, ending the call. It was a fucking Saturday.

Bucky sat himself down on the edge of the bed and set out thinking about how to handle the situation. What the _hell_ had happened to ‘three to six months’? Not even twenty-four hours ago the suppressant had still be active, apparently the only thing keeping his body from a mind-melting Heat, which—okay, which was _nothing_ like the Heats he’d experienced in the past with Erik. Those Heats had basically been ‘heat plus’; the real difference between them and normal heats had come through with the added element of an Alpha rut.

_Oh, god,_ Bucky remembered. _Steve is rutting right now_.

The longer he sat, the more difficult it became to think about anything but the burning itch invading his skin, the hardness in his sweatpants, and the smell of Alpha wafting under the doorway.

_I should go wake up Steve_, his hindbrain reasoned._ Steve is smart. Steve is my Alpha. Steve will know what to do_. There were still some logical parts of him left that understood he was actively becoming a victim to his Omega biology— but then, those other, more wildly Omega parts of him were telling the logical parts to shut the fuck up.

Bucky returned to the living room and swam through the ocean of smoky rut scent to approach the large male body laying prone on the couch.

“Steve,” Bucky said softly. He leaned down, and the Alpha stirred but did not wake. “Stevie, you gotta wake up, we have a problem and we need to talk—”

And suddenly Steve was awake, _wide_ awake, and pulling Bucky down by the shirt collar. Their mouths crashed together violently and Steve let out an incredible _groan_ that was all animal satisfaction and claiming.

The protest that had initially risen in Bucky’s throat died out almost immediately once he felt the effect of Steve’s touch, which was now pressing insistently all over Bucky’s arms, his back, his ass; it was like an icy hot balm on his itchy, Heat-flushed skin. And Steve was kissing him so, _so_ hard that Bucky could already feel the makings of beard burn on his chin.

But then, just as quickly as he had started in, Steve seemed to jolt into real, waking consciousness and sprung up off the couch like he had been burned, knocking Bucky onto the armrest in the process. Bucky was busy trying to blink away the residual lust and desire when the smell of Alpha fear hit him.

“Bucky,” Steve warned. His voice was scratchy with sleep but still filled with unmistakable fear. “Buck— I. There’s something wrong— _really_ wrong.”

Bucky gave a sigh from his spot on the couch and closed his eyes. When he opened them, Steve was staring back at him with a pained look on his face, all flushed skin covered with the glow of light sweat. Bucky suddenly had an uncontrollable urge to get on his knees and shove his hands directly into Steve’s sleep pants.

“You’re in rut, baby. And I’m in Heat.”

Steve’s eyebrows shot up.

“What?!” he squealed, and if the situation they were in weren't so freaky Bucky might have found the sound adorable. “How? I thought that wasn’t supposed to happen for another—”

“Three to six months, yeah,” Bucky finished. “But it’s here. It’s happening, now. I don’t know how. I tried to call Dr. Pete but his office is closed on the weekends.” Bucky sighed again. “Looks like we’re on our own, Steve.”

Steve’s mouth hung wide like a fish, opening and closing, eyes darting around the room like he might find a magic ‘Rut Off’ switch on the wall. Finding none, he looked back at Bucky and swallowed.

“Buck, I— I want to do some really crazy things to you right now. _Bad_ things.”

Bucky's dick twitched. Suddenly he found himself considering that maybe they didn’t actually _need_ any special advice to work this Heat out. It was meant to be all instinct, after all; biology. Maybe the best course of action was just to hand the reigns over to those instincts, to do what feels right. Plus, he remembered, he had experienced _some_ Heats before— however much smaller and less intense. But still, even with the effects multiplied by a hundred, how much trouble could they really get into together?

He vocalized these thoughts to Steve.

“I don’t— I don’t think that’s a good idea, Buck,” Steve returned, in a way that sounded like it positively pained him to say it. “I want you— _god_, I want you, wanna _do_ things to you— but I can’t, if we do I might just—”

“Look, Stevie,” Bucky cut in. His mind made up, he moved slowly across the room towards his mark, keeping his eyelashes low and swiping his tongue out to wet his bottom lip. “I hear what you’re saying, but these urges we’ve got are going to keep up for _days_ unless we do something about them.” He stopped in front of Steve—who sat, frozen— and walked his fingers up the Alpha’s left arm teasingly. “You don’t want me to be feeling miserable for that long, do you baby? Wanna make me lay alone in bed, squirming, with my own fingers inside me, _screaming_ for you?”

And that made Steve moan, loud and _oh god_ pained, head thrown back and eyes squeezed shut.

“No, Buck,” Steve ground out. “Don’t want that at all.”

“Then why don’t you take me to bed and show me all of those _bad_ things you want to do, hm?”

Steve’s breathing grew more labored— much more— but Bucky was shocked and disappointed to find that the Alpha didn’t actually budge.

_Fine_.

“I’m in Heat, baby, I _need_ a knot or I’m going to go crazy." His words elicited another hot moan from Steve and Bucky continued, a little frenzied now. “I gotta get it _somewhere_. Who knows, maybe I’ll get so needy that I’ll just start wandering the halls, calling out for the first Alpha that wants to—”

And that, apparently, was a touch too far for Steve Rogers. In a flash Steve was ripping away from Bucky and running for his front door, opening it and moving through it and slamming it shut behind him.

Bucky’s heart absolutely sank through his stomach, and he ran after Steve, only to find that a force on the other side of the door was preventing him from turning the knob.

_What the hell?_

“What are you even _doing_ Steve?!” Bucky called through the door, frustrated and pissed off and still very hard and wet in his sweatpants.

“Keeping you safe!” the Alpha yelled back, voice strained. “I can’t be in there without hurting you but I _can_ be out here. I can make sure no one else comes by trying to take you.”

Bucky sighed and pulled at his own hair.

They argued between the door for at least another five minutes, getting no where. Eventually, Bucky threw his arms in the air and forced himself to step away. He retrieved a glass of ice water and angrily plopped down on the couch, turning on the television and focusing all his energy on not rubbing his leaking ass against the furniture.

—

“Steve. Steve!” Bucky called through the door. Forty-five minutes had passed since they last spoke, but he could still smell Steve outside, barricading his apartment. “You have to come back in. My landlord just called and the neighbors are complaining about you blasting up the hallway with your rut scent.”

He could almost smell Steve’s blush through the door.

“Um,” Steve started, “I—okay. Fine. But you need to lock yourself in the bedroom.”

Bucky didn’t reply, just backed away from the door.

When Steve finally entered several seconds later, he was the picture of a hot mess. Every inch of his skin was flushed and covered in a sweat. His eyes were bloodshot. His hair was pointing in every direction, like he’d been trying to tug it right out of his scalp.

“I’m not going to lock myself in the bedroom.”

“Bucky!” Steve started back at the panicked pacing he’d been practicing all morning, refusing to make eye contact. “I know I can’t really leave— don’t _wanna_ leave, gotta _stay_ and make sure you’re safe— but you also gotta keep yourself safe from me, alright?”

“I don’t _need_ to be kept safe from you, Steve!” He was glad Steve had finally put an end to his hallway guard duty, but it wasn’t going to be much of an improvement if he couldn’t get Steve to comply. “I’m in heat— no, I’m in a Heat— and you’re my Alpha. I need to be _with_ you, baby!”

Steve had given a whole body shudder at Bucky’s mention of ‘my Alpha’, but he otherwise became still, shaking his head back and forth adamantly.

“I told you, Buck, I’ve never seen myself like this before,” Steve gritted through his teeth, voice frayed at the edges with pain. His eyes lay fixed on the carpet of the living room floor and firmly _not_ on Bucky’s face or body. “I don’t know what’ I’ll do, what I _could_ do. I might— probably _will_ hurt you.”

“You won’t hurt me, Stevie,” Bucky replied, firmly. “I know you won’t.”

“No. There is _no_ way you can know that.”

Bucky gave an exasperated groan and began his own pacing, grabbing at the hair at the nape of his neck.

“_Yes_,” Bucky gritted out, “I can and I _do_ know that. You won’t hurt me for the same reason you were just standing guard outside of my apartment.”

Steve didn’t respond or look at Bucky, but continued the rigid shaking of his head.

_Why won’t he just _listen _to me?_

“I know because your body was literally _made_ for this, Steve." Bucky was frustrated, but he made a conscious effort to keep his volume low and as calm as possible despite the way that his skin was crawling and itching with need. “Your instincts, too. You already _know_ how to do this, how to take care of me when I’m like this. It’s programmed into your DNA.”

Steve let out a shaky exhale and turned his body away from Bucky’s approach, rushing out of the living room and into the kitchen as though it were an escape portal. Bucky released an angry, frustrated moan and followed.

“What else can I say to you, Steve?” he yelled after him, all pretense of calm and collectedness now out the window. His appeals became sloppier. “I _need_ you, Steve. My body is _screaming_ for you!”

Steve’s escape route ran dry and he stopped, facing the kitchen island with his back still turned to Bucky, bracing his hands against the curve of the countertop edge. The Alpha dropped his head and let out clear groan of pain at Bucky’s words.

Honing in on what appeared to be a chink in Steve’s armor, Bucky pressed on and allowed a slight lilt and seductive whine to enter his voice.

“This is your Omega asking for his Alpha to _help_ him, Stevie,” he pressed. Steve’s whole body jerked in place, and a fresh wave of that charcoal-sweet scent rolled through the room. Bucky breathed it in greedily. “Please, baby. I feel like I’m going to explode if I can’t have your knot—”

Bucky was cut off when Steve abruptly doubled over the kitchen island and let out the loudest, most pained groan yet. He looked as though he’d been kicked in the gut.

“_Buck_— please. Please _stop_!” There was a faint but clear whine underlying his voice when he spoke. “I’m so, _so_ sorry baby—but you _have_ to stop saying those things! Hearing that I’m failing you— hurts like _stabbing_, baby, _fuck_, makes me wanna _die_.” And Bucky could hear that Steve was indeed near to tears (if not there already) as he tripped over phrases. “That I’m not giving my Omega what you need, _goddamnit_ Buck—_hurts so much_.”

Several things then happened in a perfect, terrible playback sequence. First, every cell in Bucky’s body _lit the fuck up_ at hearing Steve’s words—_ ‘my Omega’_— and his Heat decided that the only logical response was for his body to release a fresh trickle of slick from between his legs. The scent of it filled the kitchen and elicited an immediate, almost violent reaction from Steve. The Alpha’s body initially jerked upward from where he was bent over the kitchen island, as though to turn and pounce on Bucky—who barely had time to react before the Steve’s _stupid fucking iron_ _will_ kicked in and the super soldier visibly commanded himself to return to his former position. Bucky winced as he heard Steve’s forehead smack against the granite countertop with the force of the correction. Whether due to the impact or to the onslaught of Bucky’s scent—or both—Steve let out a high-pitched whine that that was clearly intended as a pained plea for mercy, and within a nanosecond Bucky’s Omega hindbrain had him returning an instinctive whine of his own in sympathy.

A few impossibly tense moments passed in the quiet of their heavy breathing. As the stillness began to swallow him, it sunk in with Bucky that Steve might literally be willing to _die_ if it meant not surrendering control to his Alpha instincts. The enormity of the thought pressed down like a hundred massive bags of sand falling onto Bucky’s entire body, temporarily suffocating the terrible itch of Heat under his skin and allowing him a moment of sober clarity.

He had basically been using his unchecked impulses to completely juice Steve with the temptation of his Omega pheromones, using his biology against him, instead of stopping to think about what was most important to _Steve_—which was, quite evidently, a guarantee that Bucky would remain safe.

Bucky knew Steve could never hurt him; any thoughts to the contrary were out of the question. But if he pressed on with his fevered attempt at seduction knowing that Steve didn’t believe that to be true, didn’t have that same faith in himself, he was effectively taking away Steve’s choice in the matter.

_Shit_, he thought,_ I am a complete fuck-up._

“Wait here,” Bucky said quietly, before turning on his heel and heading to his bedroom. He allowed Steve a brief moment of dignity and did not look back as he strode away.

He went straight to his bedside table, swiftly yanking out the drawer. When he returned to the kitchen, he felt a small trickle of relief to see that Steve had apparently taken advantage of the slightly clearer air and pulled himself upright against the countertop. He had even turned around to face Bucky’s direction, even if he still refused to actually _look_ at Bucky.

As Bucky proceeded in his march over to Steve to present the object in his hand, he quickly found that he had misjudged the Alpha’s new level of comfort. Steve staggered backwards at Bucky’s quick approach, moving as far as he could away from the Omega before the kitchen counter halted his progress. Bucky stopped in his tracks and watched Steve catch himself against the countertop ledge, directing his gaze to consider the object in Bucky’s hand.

“Do you know what this is, Steve?” he asked. Steve remained mute, but Bucky saw his throat bob and swallow thickly. “Have you seen one of these before?”

“No. Yes,” Steve faltered. “Natasha has— there was something like that.”

“This is an Alpha tase,” Bucky explained, attempting to sound every bit as cool and collected as he did not feel. He twirled the slim device around in his hand for a moment, allowing Steve to see the object at different angles. About three inches long and thin in profile with a matte black finish, the object resembled something like a small remote control. The central feature was a singular button about the size of a quarter, slightly texturized so as to differentiate it under the user’s touch. A belted strap of black leather hung loose from where it was attached at the center. “It ties to my wrist,” he said. “You can’t see it, but there’s pheromone cartridge inside.”

Bucky turned the tase so Steve could see the small opening at the forward end. Steve seemed to flinch instinctively, if only the tiniest bit, as though Bucky had pointed the barrel of a gun at him. The notion wasn’t entirely inaccurate.

Bucky exhaled and continued his explanation. “An Alpha tase is a military-grade protection device. They come in different forms, made for different applications. This type was formulated for military Omegas who have been placed in high-risk operations in close quarters with unbonded Alphas.”

Steve’s body remained ever immobile, but Bucky saw him give a small, confused quirk of the head.

“This one was Becca’s,” he explained in answer to Steve’s silent question. “She gave it to me after she was discharged and bonded to her now husband.”

As Steve continued to stare at the tase, Bucky maneuvered the device around and began to fasten the leather strap to his metal-grafted wrist. Slowly, Steve’s expression began to change to one of understanding— and something akin to relief.

“Natasha has one for Bruce,” he said aloud, appearing to deliver some partially formed statement of realization to the room around them. “That— it must be their failsafe. For missions. For the… other guy.”

Bucky hummed a sort of noncommittal assent; he may not know much about the Avengers’ operations, but it didn’t surprise him that someone in the organization would have introduced a modified Alpha tase to control the Hulk if he got out hand.

He finished tightening the strap around his wrist and adjusted the device so that the pheromone emitter faced outward from his wrist and the central button remained in reach of his thumb, although far enough away to prevent an accidental trigger. This was how Becca had told him to wear it.

“If you were to do something that hurt me— and you _won’t,_ Steve,” Bucky said, biting down on the final consonants, “all I’d have to do is press on this trigger and hold down, firmly, for three seconds. The cartridge inside would open, and the cloud of defensive pheromones that would be released would be so _thick_ that it would literally choke you into submission.”

He watched Steve breathe out shakily, something between fear and a small sense of easement.

“You would be in so much discomfort—” Bucky continued, looking at Steve even if Steve wouldn’t look at him, “—_enormous_ discomfort, even pain, that you’d practically forget what an Omega even _is_ until after it wore off— and by then, I’d be long gone out the door.”

Bucky was still itching, _burning_ with the Heat thrumming under his skin, but he steeled himself as much as possible to stop from moving further in Steve's direction. He waited for what felt like a century as Steve’s tense gaze considered the tase and, finally, flitted up to meet Bucky’s eyes.

“You— you’ll wear it, Buck?” Steve choked out. “You’ll protect yourself from me?”

Bucky couldn’t stop the way his heart leapt at the tense with which Steve now spoke; they had left the theoretical land of _‘you would’ _and entered the promising realm of ’_you will’. _His dick twitched in his sweats at the thought that Steve might _finally_ give him what he so desperately needed.

“I’ll keep the tase around my wrist the entire time,” Bucky insisted. He willed his voice not to shake with anticipation. “Super solider or not, you couldn’t stop me from using it even if you tried.”He quit before adding _‘But I know I won’t need it’_, not wanting to say anything that might lessen Steve’s confidence that Bucky could and would defend himself if the need arose. As much as he needed Steve and his super soldier knot, what he needed even _more_ was for Steve to feel absolutely secure in their actions together.

They stood there for awhile longer, suspended animation in Bucky’s kitchen, longing and fervently thinking and just _breathing_. Steve crossed his ridiculous, thick arms across his chest as if to hold himself upward, keep himself standing. Bucky watched as his right hand nervously fiddled with the outer torso seam on the opposite side of his t-shirt.

And then, finally—

“Okay."

Bucky nearly bit through his lip with the effort it took to keep from collapsing onto the floor.

“Okay?” he repeated back to Steve. After all the effort spent, and even with the Heat fever still worsening, Bucky suddenly found himself insecure and unable to move. “Okay. That’s… that’s good.”

Bucky wasn’t exactly sure where to go from there, but there was something else he needed to know before this went _anywhere_ else.

“I’m going to ask you a question, and I want you to answer me honestly.”

He stared at Steve silently until the other man accepted his eye contact. Steve nodded.

“I know you haven’t done this with an Omega before, and that’s okay, it _really_ is,” Bucky said earnestly. “But is this what you _want_, Steve?”

As he finished his question, Steve’s clenched fists tightened in his crossed arms and Bucky both saw and _heard_ the t-shirt seam under the Alpha’s right hand rip under pressure. The tear revealed a hint of skin and oblique muscles. Bucky did not lick his lips.

“_Bucky_,” Steve said, groaning low in his throat. Bucky suddenly felt strangely cruel for asking the Alpha to continue verbalizing his thoughts, but it was a necessary cruelty. “You gotta believe me when I say that I have never, _ever_ wanted anything more in my life.”

Hearing that Steve still wanted him—wanted _them_, like _this_— after the intensity of their argument shouldn’t have surprised him. Even so, Bucky felt welcome relief wash over his skin. He exhaled deeply and flashed Steve a tilted grin.

“Good,” Bucky answered. He began a slow, purposeful saunter to close the five-foot gap between him and Steve, working his just hips a little for Steve’s viewing pleasure. Judging by the way the Steve’s gaze dropped down and his clenched jaw opened just a bit, it had its intended effect. “Then I’ll just keep this here, attached to my wrist,” he said, lifting the Alpha tase and giving it a light tap for Steve, who’s shoulders visibly let go of the tiniest bit of tension.

He stopped in front of Steve, inches away but not yet touching, and lowered his voice as though he were speaking a secret that only the two of them could hear. “And you just keep _me_ attached to _you_.”

The line was too cheesy, but damnit, Bucky was really, _really_ ready for Steve to do away with the whole Captain-In-Control bullshit _this fucking instant_. He was legitimately about to combust with the need for Steve’s hands on him, which is why it pissed him off _so very much _when all he got out of Steve was a weak, pained inhale and a ridiculously careful set of super soldier hands settling gently (_gently_? fucking _really_?) on Bucky’s hips.

_Play it cool, Barnes, _he reminded himself, despite his ever-building frustration. The two of them had talked (and talked, and talked), and Steve had already agreed to let go and just be an Alpha. To take what he wants.

_Steve just needs to be reminded what that means_ _._

Doubling down on the ‘not about to completely lose it’ act, Bucky hid his frustration and cooly stepped around to Steve’s right side, where he slowly placed his chin up onto the Alpha’s shoulder. He let the cool metal of his left fingertips lightly trail across Steve’s abdominals in passing, eliciting a low moan from Steve’s throat. Bucky watched as Steve collected his hands into tight fists atop his own jean-clad thighs and eyed Bucky warily out of the corner of his eye. It was as if Steve were frozen in place trying to decide on the best way to release all of his well-crafted control.

“I want you, Stevie,” Bucky whispered. He looked up at Steve through his eyelashes.

Steve silently bit his lip in response, and Bucky saw a little bead of blood forming. Steve looked away and dropped his head all the way back. With his neck so exposed, Bucky took the opportunity to fill his nose with the Alpha’s smoky scent.

“Smell so good, baby,” Bucky said. He was thankful that he was at least _meaning_ to sound so whiny and helpless; Steve really did smell like heaven, and Bucky didn’t think he could sound unaffected even if he wanted to.

“Yeah, Buck?” Steve asked, voice shattered. The larger man cracked his eyes open and turned his head slowly.

Bucky gave a slow nod made a show of inhaling Steve even more.

“Amazing,” he whispered. “Love it so much. Want it all over my sheets, all over _me_.”

“_Fuck_,” was Steve’s response, squeezing his eyes shut yet again. “I want that too, baby. All the time.”

“You do?” Bucky asked coquettishly. “Then make it happen, Stevie. Make me smell like you.”

Bucky’s heart leapt gleefully into his throat as Steve swiftly pushed himself off of the countertop and turned towards him. For a split second, he looked ready to devour Bucky. Then, as if realizing he didn’t have a plan on exactly how to go about that, Steve shrunk back into himself a little and turned away again. While Bucky managed to keep in a frustrated groan, Steve could not do the same.

“Damnit,” Steve swore, white-knuckled against the countertop for what seemed like the millionth time this evening. Bucky heard him suck in a breath. “If you knew the things I was thinking of doing to you… it’s scarin' me , Buck.”

Somewhere in the depths of his lust-addled brain, Bucky forcibly reminded himself that Steve had never been in an Alpha rut before. Hell, Steve hadn’t even _been_ an Alpha not five years ago (in Steve Time, at least). Bucky felt a sympathetic pang for the Alpha. He straightened up a little and tried to vanish the pout from his face.

“Hey, it’s okay,” he soothed. He placed one gentle hand on Steve’s back and rubbed lightly. He made himself ignore the hard lines of hot back muscle he found there. “It really is. All those things you want? Guarantee I want them too, baby.”

Steve seemed to consider this skeptically, but remained silent.

“The first time I went into a Heat— even the _regular_ heats, the ones I’ve almost always had— I was scared out of my mind. So many things your body just _wants_— it’s overwhelming. And I’ve been on suppressants for so long, I think this would be scary anyways,” Bucky added, “if I wasn’t going to spend it with someone I trust."

Under the palm he maintained on Steve’s back Bucky felt the Alpha release a breath.

“I trust you too, Buck. With everything, _god_, I just—“ Steve tried. “I haven’t done this before and I really, _really_ want to be good for you. Don’t wanna be selfish.”

The admission just about made Bucky’s heart explode. _Motherfucker_, he thought. _I am in love with this man._

(But that was something he could _not_ address right now, not in the throes of a Heat, and Steve probably wouldn’t believe him, anyways.)

Instead, Bucky teasingly walked his fingers up Steve’s spine and reached up to play with the hair on the nape of his neck. He felt the other man shiver when he leaned in close to whisper in Steve’s ear.

“You know what the amazing thing about Compatible pairs is, baby?” he said. “It’s not just about what I want, or what you want. It’s about what _we_ want. If it feels good for one of us, it’s gonna feel good for both us. As long as we both want _this_, together.” Bucky found himself mouthing wetly at Steve’s shoulder through the sleeve of his t-shirt. “Want you so _bad_, Stevie, _god_.”

Steve leaned in to Bucky’s mouth a little and breathed in deeply. “Want you too, Buck. So _perfect_. Wanna take it.”

“Then what are we waiting for?” he asked. Bucky felt way past the point of desperation as he punctuated his speech with slow, sloppy laps of tongue, making his way upward towards Steve’s scent glands. “Need my Alpha inside me, Stevie. Gonna feel _so_ good, I promise. For both us.”

And _finally_, Bucky’s attempts at getting Steve to loosen the reigns began to show progress. Steve took a few more deep breaths to straighten himself out before standing and turning to Bucky.

And, wow, Steve really did have the most perfect, beautiful blue eyes.

“Can I kiss you?” Steve asked with all of the earnestness in the whole goddamn world, as though Bucky had not just been literally begging the Alpha to fuck him five ways to Sunday.

Bucky’s only response was to pull Steve down by the head and crash their mouths together. He tasted the sweet tang of blood on Steve's lip. The Alpha immediately moaned into his mouth and Bucky swallowed it, all eagerness and greed. He turned his head to deepen the kiss and raked his fingers through the blond’s beard, petting at the strong jawline underneath.

“Come on, Stevie,” Bucky gasped, before diving back in and licking into Steve’s mouth. “Touch me. Wanna feel you.”

Steve sucked in a breath through his teeth and seemed to reflexively bite down on Bucky’s lip. It was certainly hard enough to sting, but not near enough to draw blood. Even so, Bucky felt Steve start to go rigid again, clearly freaking himself out with the magnitude of his instincts and desires. And _hell no_, Bucky would be having _none_ of that, not after all the emotionally exhausting work he had done to get Steve to this point, even with his blood still pounding with _WantWantSteveWant _and _AlphaNeedWantNeedAlpha_. He was going to have to pull out the big guns, it seemed.

Bucky broke from Steve’s mouth and grabbed Steve’s left wrist from where it sat gently against Bucky’s hip. As he held Steve’s arm in his flesh hand, he made a wicked show of licking a wet, purposeful stripe across the scent glands on Steve’s inner wrist. He watched blue eyes go impossibly wide, and Bucky urged Steve’s big body (_so_ fucking _big_) against the countertop behind him. Steve went willingly, steadying himself against the edge with his unoccupied arm. Bucky used the fingertips of his metallic hand to trace subtly over one of Steve’s nipples, which earned him another low moan. Through his tongue and the tips of his fingers, Bucky could feel Steve’s entire body vibrating with need.

“Come on, _Alpha_, please” Bucky whispered, so low it wouldn’t have been audible to someone standing three feet away. “Knot me. _Breed_ me”.

Bucky heard Steve suck in one gasping breath before the Alpha’s entire body stilled and the firm lines of Steve’s form went impossibly rigid. Every fiber and tendon in Steve’s body looked to be strung tighter than a violin.In the same moment, Steve’s once potent scent bizarrely vanished from the room, as though the Alpha had withdrawn every last pheromone back into his body with that one inhale.

The entire room filled with stark nothingness for that flash of an instant. Bucky thought that the very time-space fabric of his apartment had surely become suspended around them. He imagined even the chemical structure of his own floating, fluttering pheromones must have shuddered to a stop mid-air, freezing in place in anticipation to see what their Alpha target would do next.

And _oh—_ Steve _growled_.

Although a ‘growl’, Bucky thought, was a wholly inadequate term for the noise Steve made. He had _never_ in his life heard a human make the sound that Steve was making in that moment, not even in the movies. It was more than a growl but Bucky understood it, like the most raw and visceral language he’d ever known. It spoke of _Need _and _Take_ and _Now_ and, most importantly to Bucky, _Mine_.

_Yes, _Bucky’s body sang in response. _Yours, all yours._

Where Steve had been reserved and controlled only seconds before he was suddenly anything but those things now.Two enormous super soldier hands were gripping around Bucky's waist in an instant, lifting him up off the floor like he were made of paper and setting him down on the countertop. Bucky opened his thighs without a second thought and let Steve fit himself right between them.

Steve was so so close now, moving everywhere, too much for Bucky to get a good look at Steve’s face— but his Alpha _scent_, laden with arousal, returned to the room with a thousandfold strength. It hit Bucky like a perfect wall of cinder blocks, and he let out a high-pitched whine, pondering the best way to drown himself in the smell of _Steve, Alpha, yours_.

He didn't think it would ever be enough.

Bucky felt himself producing new slick and he realized was probably starting to soak the countertops. He did not care. The worst of his Heat was returning in full force now and demanding _everything_, from himself and from Steve.

“Alpha,” Bucky whined, this time out of only hindbrain instinct instead of a cheap shot at seduction. He began smothering his face in the hot skin of Steve’s neck and looping his arms around Steve’s shoulders, squirming around on the countertop, nearly shaking with his need. “Need your knot, _please_.”

Steve groaned out his approval of Bucky’s demand and once again moved to take his mouth. His kiss, if it could even be called that, was positively brutal.

Strong hands moved down Bucky’s sides, palms pressing hard and lighting up Bucky’s skin with friction of his shirt along the way. When Steve reached his hips, he squeezed hard and brusquely slid his hands beneath Bucky’s sweatpants. The stark contrast with the almost shy Steve of their previously physical encounters told Bucky all he needed to know about his success in getting Steve to surrender to his inner Alpha.

Once inside Bucky’s sweats, Steve scooped each of his ass cheeks into his hands and squeezed, hard—almost enough to bruise. His fingertips were pointed inward towards the seam of Bucky’s ass, and Bucky could sense the moment Steve first felt the Omega’s slick make contact with his fingers. He felt himself grow even more wet as Steve’s pleased and possessive growling reverberated through both of their chests.

“Fuck yes,” Bucky hissed.

Steve’s hips gave several quick, uncontrolled stutters where they were being held between Bucky’s thighs as the scent of wet Omega grew even more dense than before. As though the smell snapped yet another piece of the Alpha’s willpower, Steve suddenly used his firm grasp on his ass cheeks to lift Bucky off the countertop a few inches, and Bucky instinctively complied with the unspoken demand to wrap his thighs around Steve’s slim hips. The new position forced their clothes erections to rub together. Bucky moaned loudly and his whole body broke out in a fresh sheen of sweat.

Steve responded by roughly shoving the tips of his fingers further between the globes of Bucky’s ass, causing Bucky to release another filthy moan into Steve’s open mouth. He felt the pads of Steve’s fingers flex and tug against the edges of his soaked entrance.

“Please,” he begged. “Stevie, please—“

Then Steve was thrusting the thick middle fingers of both of his hands past Bucky’s rim and gravity was pulling Bucky’s body down to swallow them to their first knuckle. The sudden sensation made Bucky nearly scream with delight as he reveled in the stretch and the promise of a knot.

“Fuck!” Bucky sang. Steve quickly swallowed his curse before Bucky threw his head back and squeezed his eyes closed, still, shutting out everything except the sensations that exploded his nerve endings where his Alpha was touching him.

They stayed like that only briefly before Bucky started up his squirming again, feeling almost helpless, this time attempting to rock downward and coax Steve’s fingers further inside.

Steve suddenly seemed to become angry and irritated with Bucky’s restless wriggling. In a sequence that almost looked practiced (which, Bucky knew, it could not have been), the Alpha effortlessly shifted all of Bucky’s weight into the wide palm of his left hand and yanked his right hand out of the sweatpants completely. The abrupt shift forced Bucky’s ass to swallow the entire length of the finger still inside him, and he felt a second finger suddenly positioned just outside his rim.With his newly freed right hand, Steve was swiftly reaching up to the back of Bucky’s neck and _gripping_.

Every tendon in Bucky’s body fell lax as biology kicked in and his muscles were suspended in a forced state of release due to the Alpha grip. His nose was immediately engulfed with a brand new scent, which some barely-there part of his brain recognized must have been the specialized calming pheromones that Alphas could produce for Compatible Omega partners. Bucky inferred from the thickness of the scent that the source was the gland in Steve’s wrist, now hovering just to the side of face while Steve gripped him.

A warm wave of tranquility washed over him. In his stupor, Bucky mused that not even five minutes ago Steve had been standing in his kitchen moaning about his self-control and refusing to even touch him. Now, he had Bucky’s helpless body _speared_ on Steve’s finger in his ass and practically dangling from his strong Alpha grip. It was like the Alpha had suddenly discovered every item in his biological toolbox all at once.

Bucky had never been happier in his life.

“Omega,” Steve growled out, exuding triumph after his successful attempt at taming Bucky. His eyes were glazed over, pupils blown wide as they stared into Bucky’s, all heavy eyelids and full, dark blond lashes. “Mate.”

_Goddamn, _Bucky thought. _His rut is practically feral._

“Alpha,” Bucky weakly whispered in response. He could barely move his mouth (which he knew was drooling) under the command of the grip. Steve seemed to notice this and eased up slightly, apparently feeling comfortable about Bucky’s continued submission. “Bed. Nest?” Bucky tried his best to sound convincing.

Steve nodded his approval and released Bucky’s neck to wrap his arm around his waist again, supporting him as he began the short walk towards the bedroom. Bucky kept his thighs wrapped around Steve and continued to bask in the drugged feeling that was already started to ebb from his brain. Faintly, he noted that Steve still had a finger stretching his hole open, rubbing just inside his rim gently as Bucky’s body bobbed up and down with each of Steve’s steps. He could hear himself purring lowly in appreciation.

The next thing Bucky knew Steve was setting him down on the mattress and drawing his hands back from the Omega’s body. Bucky whined at the loss of the finger in this ass; the residual calming effects of the grip and Steve’s special Alpha calm were wearing off, and he could feel the itch under his skin growing again. Luckily, Steve’s hands were back on him within seconds.

“Clothes,” Steve grunted. Even though his gaze and his words (or lack thereof) made him seem more like animal than man, Steve seemed oddly controlled as his hands adeptly maneuvered Bucky out of his t-shirt and sweatpants. An approving growl rumbled in Steve’s chest when Bucky was finally bare on the bed in front of him. He knew what he must look like, all sweaty skin and flushed erection laying hard against his belly, but Bucky couldn’t bring himself to be self-conscious enough to blush. He needed to get at Steve’s skin, _now_.

From his position on his back, Bucky pressed himself upward with his elbows and reached out one hand (slowly, so as not to freak out Steve) to tug at the bottom on the Alpha’s t-shirt. “Off?” he asked, looking up at Steve with his best _pretty please _face.

The expression in Steve’s reaction suggested that he was pleased at Bucky’s request (if not a little confused about his Omega’s priorities), and Bucky sighed contently as he watched the larger man strip off his top. He would never tire of looking at the long lines and gentle dips of Steve’s chest and torso.

But, right now, Bucky’s Heat really needed to get more data about the situation in Steve’s pants. 

Bucky scooted himself to the edge of bed, knowing but not caring about the literal trail of slick he left on the sheets in his wake. When he got to the end he fell forward and collapsed onto his knees in front of Steve. Bucky wasted no time placing his hands around Steve’s thighs, pushing his face forward to rub against his jean-clad crotch. He inhaled _deep_.

He had always found the term ‘Alpha musk’ to be a bit cliche. It certainly didn’t bring any justice to the minute details that together made up an Alpha’s unique scent. This close up, he got Steve’s usual smoky scent mixed with earth and sweat and yeah, it smelled like cock and it wasn’t exactly glamorous, but it was _exactly_ what Bucky needed to be breathing in at that moment. He expressed as much with a muffled hiss of, “_Yes_,” exhaling against Steve’s denim.

Bucky’s pressed his open, wet mouth against the outline of Steve’s rock hard cock through his pants and let Steve hear him whine for it. That got the Alpha’s attention, but he made no immediate move to open his jeans. When Bucky looked up with a pout he could see that Steve had managed to reign in the caveman act a little bit, appearing content to just watch Bucky’s frustration for a short moment.

_Fucking fine, then, _Bucky thought. _I’ll do it myself._

Even buried in the absolute haze of his Heat, Bucky somehow made quick work of Steve’s button and zipper. He was happily shoving the jeans and briefs off of Steve’s hips in just a few seconds. Bucky immediately felt the little smear of precum against his nose where Steve’s enormous cock spilled forward and literally _slapped_ against Bucky’s face.

“Oh, _christ_,” Steve moaned in shock at the sight. Bucky grinned inwardly.

Bucky braced his palms against the front of Steve’s thighs and let his mouth fall forward, seeking out the purpled head of Steve’s cock and letting it press against his bottom lip. Not entering his mouth, just… enjoying the pressure. He pulled away and licked a wet stripe up the underside before rubbing his cheek against it.

“You like that,” he heard from above. Steve’s voice was hardly above a whisper but it was still all gravel (_and shit… was that little Stevie finally attempting dirty talk?_).

“_Mmm_,” he moaned in response, “_fuck yeah._” He really did.

He moved his metal-grafted hand from where it sat on Steve’s thigh to wrap around the Alpha’s thick erection, beginning to really use his mouth on it at the same time. With his flesh hand he reached down to press the palm against his own dick, allowing himself a modicum of relief.

Steve allowed this worship to continue for awhile longer, pants around his knees and needy Omega damn straight _slobbering_ on his cock. When Bucky decided to tease the tip of his tongue against the spot at the base of Steve’s cock where his knot would pop later (_inside_ Bucky, _fuck yes_), the Alpha shoved both of his huge hands into Bucky’s hair and (very, very firmly) guided him upward.

Bucky gave a little whimper at the loss of heavy Alpha cock on his tongue, but he had little time to mourn before Steve was manhandling him back onto the bed. He threw Bucky down on his back again and then stopped, still standing at the edge of the bed, his hulking form almost a silhouette in the dimly lit bedroom, broad chest heaving and fists clenched at his sides.

He was a beast of a man.

Continuing to stand in his place, the Alpha furrowed his brow slightly as if realizing that he didn’t have a plan for what happened next.

Lucky for Steve, his Omega had some ideas.

“What do you want, Alpha?” Bucky drawled. “You wanna get inside me? I bet that’s _all_ you can think about right now.”

Steve’s body jerked forward as if being dragged by a magnet. He bent over Bucky on the bed, reaching his thick arms out straight and caging Bucky in. 

“_Yes_,” Steve moaned in agreement. “Need you.”

Bucky hummed low in his throat and reveled in being this close to Steve once more. It was not lost on him that in their position, all he would have to do is spread his legs and Steve could take right to fucking him into the mattress.

“Okay, Stevie.” Bucky smoothed one hand over Steve’s bicep while the other kept him supported. He let his eyes fall shut and rubbed the tip of his nose against the collarbone in front of his face. “How do you want me?”

Steve let out another growly moan as he struggled to comprehend the question. But instead of answering, Steve swooped his head down to capture Bucky’s lips in another wet, rough kiss that felt like claiming. He eventually pulled back far enough to speak.

“Need to get you ready for me,” Steve breathed, before grabbing at Bucky and heaving them both to the center of the bed in one easy push.

When they landed, Steve’s face immediately disappeared into the crook of Bucky’s neck, laving over his scent glands. Big hands pushed his thighs apart and Bucky let out a positively whorish moan. He couldn’t help it— everything _Steve_ was clouding his senses and smothering him in beefy, Alpha perfection.

He was going to remind Steve that he was in a very real _Heat_, goddamnit, and his body was already gonna be open and ready to take his knot—but, then, the Alpha moved to readjust his position and the giant wooden beam swinging between Steve’s legs _thunked_ against the inside of Bucky’s thigh, and yeah—_okay_, maybe he could wait a few extra minutes for a little prep if it meant Steve’s cock not physically splitting Bucky in half.

“_Fuck_, baby,” Steve swore as he gave Bucky two fingers to start. “So fucking _wet_ for me.”

Bucky’s body _sang_ at the penetration and produced even more slick for Steve, who began diligently pumping his fingers in and out of Bucky’s body at a punishing pace. He dragged his hot mouth down Bucky’s chin, his neck, his nipples. Obscene squelching sounds and the heavy scent of wet Heat filled the bedroom. When Steve slid in a third finger without letting up on the pace, Buck could swear that there must have been actual _splashing_ going on each time Steve pressed in to the final knuckles. Judging by the blissed-out puppy dog look on his face as he swirled the tip of his tongue around Bucky’s navel, Steve didn’t mind getting splashed.

And then Steve, ever the little angel, licked a hot line along the underside of Bucky’s cock. Bucky _squealed_, but the noise only served to spur Steve on because the next thing he did was swallow him Bucky to the root in one go.

“Steve!” Bucky cried. On any other day he would have done embarrassing things just to have Steve Rogers’s mouth sucking his cock, but today he felt like he was going to die from _too much too much toomuch_.

His distress was apparently enough to grab Steve’s attention, because he pulled his mouth away with a jolt— which, okay, probably for the best— and immediately moved himself back up to be level with Bucky’s face. His feral demeanor seemed to be quickly forced aside in favor of something that Bucky could only describe as 'Alpha panic'. Bucky might have fawned a little at the protective, concerned look on Steve’s face if not for the fact that he had also _removed all of his fingers from Bucky’s ass_.

“What is it, Buck? Did I hurt you?”

Bucky tried to respond, to reassure him that he was fine— just needed get fucked, like _yesterday_—but all he managed was a frustrated moan.

“_Shit_, baby, I’m so sorry.” A panicked Steve moved his dry hand up to lightly touch the little Alpha tase strapped to Bucky’s wrist, as though urging Bucky to remember that he had the power to stop anything Steve wanted to try (and yeah, to be honest, Bucky had completely forgotten it was there— not that he needed it). He shifted his hand to cradle the side of Bucky’s face in silent, unnecessary apology. “Do we need to stop, baby? We can stop, _I_ can still stop—“

And if Bucky didn’t feel like his blood was hot enough to spontaneously vaporize if he didn’t get a cock _right fucking now _he might have found it adorable that the Alpha was mindlessly rutting his monster erection into Bucky’s hip even as he professed his promise to call it quits.

“No!” he yelled out, pleading and groaning. “I don’t need you to _stop_, Steve, I need you to flip me over and fucking _fuck me_!”

He watched as Steve’s features filled with relief, before darkening to a new shade of arousal in frighteningly rapid succession. He grabbed Bucky’s hips, _hard_, swooped his head down to take Bucky’s mouth in a fast, filthy kiss, and then skillfully tossed him over onto his stomach like he weighed nothing.

_That is _never _going to stop being hot, _Bucky thought.

He landed face-down with an audible ‘_oof’_and Steve’s broad hands were instantly on him— calloused palms and fingertips running over his back, his ass, the sensitive skin on the inside of his thighs. The needy whimpers being extracted from Bucky seemed to rile up Steve even more.

“Yeah, baby,” Steve moaned hotly. “Gonna fill you up.”

“_Mmph_!—” Bucky whined in response, trying his best not to bite straight through his lower lip. “Need it now, _please_, all of it."

And then Steve’s thumb was pressing hot circles around his hole, dipping in and pulling back out, stretching his rim to the side like he was testing to see how far it could go.

“Still too tight, Buck,” Steve said. He sounded like he was making his best attempt at voicing unaffected observation, but Bucky didn’t miss the frustration and regretfulness lacing his tone. “Need to give you more.”

Before Bucky could protest Steve was making good on his promise, stuffing him with the three fingers he’d been using just a moment ago before working in his little finger alongside them. He could feel that Steve was trying to keep them all in a straight line instead of bundling his fingers together, four across, wide, _so_ wide, and Bucky couldn’t stop himself from tucking his knees under and pressing his hips back. His greedy body was thrilled with the added stretch. He buried his face in his forearms atop the mussed up linens of his nest and just let himself revel in the burn.

As he focused on adjusting to the stretch of the four thick digits in his ass, Bucky noticed Steve’s deep huffing breaths become quicker behind him, shallower, with the slight wheeze of an Alpha trying to control his own excitement. Then Steve pulled all of his fingers out and replaced them with one thick thumb, shoving in _hard_ past the last knuckle and then pressing _down _against the sweet bundle of nerves inside Bucky’s channel.

Bucky _howled_.

Steve gave an excited growl and did it again, pulsing his thumb down over and over and trying his best to destroy Bucky with the force of his pleasure. He took his four other fingers, no longer inside Bucky’s ass, and stretched them downwards to cup around Bucky’s balls. Steve _squeezed_, just lightly, but enough to massage another helpless cry out of Bucky. The mental image of Steve literally _holding_ his asshole and his balls together in one large, strong hand almost made him come on the spot. 

“_Shit_, Steve!” Bucky cried out. “Gonna go _crazy_ if you don’t knot me soon, fuck me, _please_—”

No longer able to control himself, Bucky slid his hand down to wrap around his cock as Steve continued his rough ministrations, but Steve saw and batted it away. Before Bucky could even whine in protest, Steve’s idle hand was covering his length and squeezing, pulling, jerking him just right.

“Fuck, baby,” Steve chuckled, darkly. “You’re leaking for me here, too, aren’t you?”

Just when Bucky thought his brain was actually going to short out from the _quadruple_ sensation of the pulsing on his prostate, his balls rolling in Steve’s warm grip, the exquisite tug on his cock, and _fuck yes dirty talking Steve_, the Alpha bent down and swiped a fat lick of his tongue right over the place where Bucky’s rim was stretched around Steve’s thumb.

Bucky’s orgasm _ripped_ through him. The force of it made him clench down against Steve’s thumb inside him and spurt rivulets of watery Omega come over Steve’s fist. Still working his hand on Bucky’s cock, Steve pulled his hand out of Bucky’s ass and grabbed one full cheek, forcing it to the side and exposing his abused hole to Steve’s view. Bucky pictured how he must look to him: ass in the air, hole all pink and pulsating and clenching, shiny with slick— probably a little swollen from being overly stretched already. The image sent an unexpected second wave of orgasm crashing down over him.

His world whited out.

When he started to come around (what could easily have been a full five minutes later), the first thing he heard was a peaceful buzzing in his inner ears. The _second_ thing he heard was an incessant stream of little whines and needy whimpers. Bucky first assumed that the noises must have been coming from himself, until he finally registered the clear sensation of Steve’s entire _face_ buried between his ass cheeks. The Alpha was feverishly lapping his tongue against Bucky’s hole, _slurping_ over and inside his entrance, again and again, mewling like starved little kitten and practically drinking Bucky’s warm slick like he needed it to stay alive. He kept the globes of Bucky’s cheeks spread apart with his hands while he consumed him.

Bucky was very much still processing all of this sensory input when he felt the wet scrape of a soaked and bearded Steve Rogers chin against his taint. The feeling shot straight to his dick, and Bucky took a second to marvel at how the hell he could still be this hard before he remembered that _oh, yeah, Heat_.

After basking in the feeling of having his ass worshipped for a few more seconds, Bucky’s hindbrain soon sent out an urgent memo reminding him that he had not yet acquired a knot, which was unacceptable on the whole.

He slowly raised his upper body up with his elbows and began to turn his head, ready to tell Steve that this was simply _wonderful_, truly, but they needed to get to the main event. But when the movement caused Bucky to shift his hips, potentially looking as though he was angling to leave the nest, Steve let out a panicked growl against his entrance and shot his right arm out to press down on the back of Bucky’s neck.

It wasn’t a true Alpha grip, not really, but Steve’s message was clear. Bucky immediately obeyed and surrendered all control he had left, let his body collapse back down onto the sheets.

“_Okay_, okay,” he conceded, crossing his forearms beneath him and settling back in, burying his face. “I won’t move, alright? I’ll stay still, just take what you need, _sheesh_. Down, boy.”

Steve replied with an unimpressed but mostly contented grunt and resumed his mission. Bucky moaned and waited, patiently, while Steve took his fill. It was glorious— _god_ it was, all lips and tongue and wet sounds and beard burn— but Bucky knew that if this kept up forever then he would definitely come again and that absolutely could _not_ happen without a knot inside him. The Heat under his skin might actually burn him alive if it did.

Thankfully, he felt Steve start to relax his movements and slow his breathing after several more long, frantic moments of eating Bucky out. When Bucky finally felt the contact of cold air against his wet, sopping cunt instead of Steve’s face, he peeked back through the gap in his crossed arms and saw Steve sitting back on his haunches, prodigious cock held in hand but not stroking himself. He had his head tilted to the side a little and he kept moving his gaze between Bucky’s ass and then down at his own dick, then back again, brow adorably furrowed in thought. Bucky’s heart melted when realized that Steve was trying to decide if Bucky was finally open enough to take him.

“_Please_, Stevie,” he moaned. He wiggled his ass just a bit, a visual reminder to Steve that he was already good to go, ready, prepped, _presenting_ for his Alpha.“I’m ready, we’re ready. Will you _please_ just fuck me?”

“Okay,” Steve replied, voice quiet and throaty and strained, but still decisive. He shuffled forward on his knees and pulled Bucky’s hips back until they met near the middle. “You’re in control, alright Buck? Promise— promise me you’ll use it if you feel like you need to.”

Bucky knew that Steve was referring once again to the Alpha tase discreetly strapped to the inside of Bucky’s left wrist. He rolled his eyes where Steve couldn’t see.

“I promise, okay?” As he spoke, Bucky slowly reached his metallic hand back between his kneeling legs and grabbed Steve’s thick shaft, maneuvering them until the broad cock head was resting against Bucky’s slippery entrance. He made a little show of flashing the tase in the process, hoping it was a comfort to Steve. “I do. I promise. If I feel like I need it, I’ll stop you.”

Steve moaned a little on his next exhale and took over for Bucky’s guiding hand.

“Thank you,” Steve said, voice briefly sober and full of sincerity. Bucky’s shoulders sagged in relief upon hearing that Steve was apparently satisfied, finally, with their negotiations.

But when Steve spoke next his tone was distinctly edgier— darker. Bucky shivered.

“I am going to fill you up _so _damn good, baby.”

And then Steve’s cock was _pushing_ in, breaching him and claiming him and _ohgod_ just _stretching_ him wide. If Bucky’s brain weren’t so lost in the ecstasy of finally— _finally_—getting what he wanted, he might have stopped to wonder how it was physically possible for Steve’s cock to feel even thicker than it looked.

“_Yes_,” Bucky hissed. “_Yes_, Stevie, oh_godyes_.”

Steve wasn’t even fully sheathed yet but Bucky could feel the Alpha trembling a little where his hands were wrapped around Bucky’s hips. It was clear that he was fighting (and winning, really) against a primal urge to just slam in all at once. A part of Bucky sort of wished that Steve would just give in, just start wrecking his cunt from the get-go, but he also understood (vaguely, begrudgingly) that the both of them probably just needed a slow moment to start— for Bucky to adjust and for Steve to keep from losing himself completely.

Every nerve ending in Bucky’s body lit up when the girthiest part of Steve’s long shaft (without a knot, at least) grazed over his sensitive prostate. Bucky moaned through his teeth where he was biting down on his own lower lip, and Steve answered with a hot groan of his own.

“So tight, Buck, _god_.”

If Bucky were just a sinful little voyeur looking on from the corner of the room then he’d probably have mocked the cheesy, passé Alpha trope of _‘oh, so tight, my perfect Omega’— _but _goddamn_ if there wasn’t a really valid point to Steve’s brutish observation. Steve had prepped him with four thick fingers and what felt like an hour straight of tonguing his ass open, and Bucky _still_ felt like they might barely make the fit work.

(_Well, spatially, at least_, Bucky thought. The stretch and burn was actually _really_ working for him.)

Finally Steve got himself seated all the way inside, Bucky’s balls brushing back against Steve’s larger, heavier pair. Steve bent at the hips to cover the expanse of Bucky’s back with his muscular body and just held them together for a moment, slowing their breathing and running a hot tongue over Bucky’s glands, scent-marking him.

And Bucky felt so _full_. In every way.

But Steve hadn’t moved yet, and Bucky needed more than just fullness— he needed to be knotted. He pushed his ass backwards into Steve’s hips, which both provided some much-needed friction and made Steve’s cock press even deeper into Bucky.Steve gave an appreciative moan into his ear as Bucky tilted his hips forward again.

He repeated the motion several more times, back and forth, purring happily into the sheets as he ground himself in circles against Steve’s lap. Despite his baser urges he kept his movements languid, encouraging Steve to enjoy the feeling of Bucky just grinding on his cock.

Soon the faint sting of Steve’s size faded almost completely, and all that was left was the warm rapture of having the other man inside him. The room swam in the scents of both their arousals, of happy Omega and of Steve’s own pride for making Bucky smell like that. Bucky wanted to stuff it into a cologne bottle and keep it on him forever. 

Soon the itch of the Heat was crawling back and reminding Bucky that they hadn’t yet finished the job. Steve’s animal rut was apparently on the same page, because the next thing Bucky heard and felt was the rumble of a growl where Steve’s chest was against his back— and then Steve pulled his hips back and _snapped_ forward, slapping against the wet skin on the back of Bucky’s thighs. 

“_Fuck_!” Bucky screamed. Steve felt perfect, glorious, and all Bucky wanted from here until forever was to be _taken_.

Steve sat back on his knees and did it again, this time pulling out almost all the way before grasping the Omega’s hips and slamming Bucky’s _entire body_ backward onto his hard length. Then he pulled Bucky up, forward, then back down— _hard—_and repeated it all again and again. He wasn’t so much fucking Bucky as much as he was fucking his own cock _with_ Bucky.

About every third thrust Steve would brush his prostate (or completely nail it), and Bucky saw stars. The wild and undignified noises he could hear himself making must have been doing it for Steve, who suddenly started unleashing the _filthiest_ language anyone alive had ever heard from Steve Rogers.

“_Yeah_, baby. Like the way your Alpha fucks you? You _do_, you fuckin’ _love_ it—”

His words never make a lot of sense—

“—gonna get my pups in you, Buck. You ready? Gonna look so _good_ like that, so _big_— gonna smell like me, and _everyone’s_ gonna know who you belong to—“

And they were almost always distorted by hot, ridiculous growling.

“Wanna—can’t wait, _mm_—gonna make you _take_ this knot—gonna make you comeonit—”

But that none of that stopped Bucky’s dick from weeping onto the mess of sheets below.

Eventually Steve seemed to decide that he needed something different. He stopped all motion and pulled out to shove Bucky forward, down, tugging Bucky’s knees out from under him and forcing Bucky’s face into the sheets. His insistent motions were punctuated by heavy, territorial growls, like Bucky himself was a heat nest and Steve needed to aggressively rearrange him to his liking (and _oh_, but next time they would have time to build a nest, next time they could have it _all_). Bucky let himself be man handled; he could die being this Alpha’s rag doll and he would die a happy man.

Once he had Bucky where he wanted him— flat on his belly, arms stretched out above his head, legs straight and knees pressed together— Steve straddled Bucky’s thighs and braced his weight on the hand planted next to Bucky’s head. He rested his other hand against the small of Bucky’s back as if to steady them both and then started rutting his hips forward, sloppy and probably a little blindly, until he finally caught the right angle of approach and his thick cock sunk back into Bucky’s body.

Safe inside again, Steve let out a tiny sated purr of his own and placed both hands on the bed, allowing him to equally distribute his body weight when he began to piston his hips forward and back, fucking him.

This position, Bucky quickly learned, was _really_ fucking fantastic because, well, one— it meant that Steve could fuck down hard, _so_ fucking hard, but still have most of the shock of his super soldier force be absorbed by the mattress beneath Bucky instead of snapping Bucky in half, which Bucky could tell was clearly by design; two— the narrow setting of Bucky’s hips and thighs, no longer spread, meant that his ass was just _that much_ tighter on Steve’s cock, and Bucky’s hindbrain preened at the thought of his Alpha taking pleasure in Bucky’s smaller body; three—Steve could enjoy all of this while still looking down and maintaining what was apparently a pretty fucking fantastic view, if the litany of obscene and broken commentary being huffed into Bucky’s neck were anything to go on; and four— it dead-centered Bucky’s prostate _every. single. time_.

“Yeah, take it,” Steve ordered, and wow, oh _wow_, how his little baby Alpha with rigid control issues was _so_ far gone now. “Take all of me, Buck.”

“Want it, baby, _uhn_,” came Bucky’s broken, whiny agreement. “Want all of you, gotta _gimme_ all of you. Gotta gimme your knot, _oh_—”

And then it was as if Bucky had finally conjured the magic beast by talking about it, because the next thing he knew he could feel Steve’s knot just start to swell at the base of his cock, beginning to press against his rim and even struggle past it on the deeper thrusts. 

The sensation had Bucky _elated_ for all of three seconds before Steve, the big motherfucker, ceased movement and— _how_?— paused for what felt like an hour, even though Bucky knew it was more like one second. The few remaining brain cells in Bucky’s skull absently noted that the half-blown knot resting against his entrance seemed to have a heartbeat all it’s own, which was weird, maybe Alpha cocks had some special set of veins to—?

A sudden and firm push against the inside of his thigh jolted Bucky from his scrambled egg-brain thoughts. Steve was roughly shoving Bucky’s legs apart, _wide_, settling in between them without ever removing his cock from its snug home inside Bucky. Big, warm palms grabbed at Bucky’s hips and the flesh of his ass cheeks, pressing down and almost kneading him as Steve continued to adjust their limbs. Their previous position had been great but this—_this_ gave Steve perfect access to press fully into Bucky’s body, not a micron of space between them. _This_ was how Steve Rogers wanted his Omega to lay while he knotted him.

That final thought instantly made everything very real in Bucky’s Heat-addled brain. Everything— every touch, every moan, every raw growl and every bead of sweat— it was all going to culminate in this one, brief flash of heat and light and pure, entropic pleasure. 

“_Fuck_ yeah, Alpha, knot me.”

Steve thrust in one, two, _three_ times and then Bucky was crying out and coming harder than he ever had in this life. The force of it further drenched the sheets that were rubbing against his untouched dick. Long, undulating waves of pleasure had him rhythmically clenching around Steve’s cock and the rapidly filling bulge at its base, massaging it towards absolute fullness. The knot caught more firmly on his entrance with each thrust, but he could sense Steve’s rut telling him that he just needed to fuck Bucky that much harder— which he then did, with frightening conviction. 

As soon as Bucky felt himself easing down from his orgasm, knowing that several more would come in quick succession once they were fully tied, his mind cleared enough for him to notice the string of deep, animalistic noises breaking loose from Steve’s chest. Then the Alpha was suddenly hooking one thick forearm under Bucky’s chest and another under his left knee, reeling him back all the way to press completely against Steve’s hard body and, _finally_, ramming the engorged base of his cock past Bucky’s bruised rim.

This time Steve left the knot in and it at last blew wide, to full capacity, sealing their bodies together. Bucky’s Omega biology had every muscle instinctively clamping down around the knot, which was big, _too_ big, and Bucky closed his eyes and cradled it inside his body like it was the only thing keeping him alive.

While Bucky’s third orgasm of the night had its way with him, Steve’s first was only getting started. Knotted, the Alpha gave a series of aborted little thrusts before giving up, then used his leverage under Bucky’s chest and leg to roll them ninety degrees and plant them on their right sides. The move made the knot jostle roughly against Bucky’s prostate, shocking another surprised wave of pleasure out of him. His dick, no longer trapped against the bed, shot an admirable spurt of watery come onto his stomach.

Once they landed back on the mattress Steve’s hands were immediately all over Bucky’s front, possessively groping and squeezing, attacking his chest, his hips, even the soft skin of his over-sensitive balls.Bucky pushed aside the overwhelming sensations to focus on the feeling of just _Steve_— the Alpha who was currently spilling boundless measures of hot seed into his body, and who would continue to do so for as long as they were tied.

Steve’s tactile assault on his skin eventually stopped, and the devastating vibrations that had wracked Bucky’s body were reduced to a satiated humming. But, against his back, Bucky could feel that Steve was still strung as tightly as before.

No— _more_ tightly that ever.

The observation concerned Bucky; Steve’s work was over, his biological imperative sated by the knot. He should have been purring with happiness, relaxed, basking in the long, drawn out climax that Alphas enjoyed, not... growling with _pain_.

“Steve?” Bucky whispered. He wished he could see the other man’s face. “Baby, what’s wron— _mmph_!”

And then a big hand was clamping down over Bucky’s mouth, silencing him instantly. Bucky’s first reaction was to assume that Steve’s extra intense rut was just egging on his dominance streak for a little longer than Bucky had expected— but then Steve loosed a chilling, _guttural_ rumbling noise directly next to Bucky’s ear and he felt hot, humid breaths against the side of his neck before Steve’s broad tongue was out and laving over Bucky’s scent glands, and—

_Fuck!_ Bucky cursed in his head. _How the _fuck_ did I not think about this?!_

He had taken Steve, a highly Compatible Alpha— and one that had never experienced even a small rut before, had never been introduced to the dark side of his biology—into his bed and _begged_ him to help him through his Heat. And Steve had fucked him, and knotted him, and made him scream and cry and sing and question everything he ever understood about Compatibility and what it could be like.

And now Steve was going to bite him.

Which— on the whole at least— was not the _worst_ thing that could have happened to Bucky. He may not have had a chance to tell him yet, but he knew he loved Steve Rogers; if they’d had more time (_or at least, like, any real warning whatsoever_) before his Heat surprised them both then maybe they would have talked about making the bond, decided it was something they wanted and pursue it, together. But they hadn’t had that discussion, and it was probably too early anyways, and Bucky didn’t even know if Steve felt the same, if Steve _wanted_ Bucky as bondmate.

Steve’s open-mouthed panting grew more labored. Bucky felt the scrape of incisors at his neck, but no pressure— just an odd sort of hovering punctuated by periodic assaults by Steve’s tongue. For now, at least, the Alpha was keeping his actions limited to obsessively attending to Bucky’s scent glands. A primal part of Bucky briefly protruded through his panic to delight at the thought that the licking would leave him scent-marked for _days._

The thought pulled an involuntary little moan from Bucky’s throat. It was mostly silenced by Steve’s hand, but the vibrations were apparently enough to spook Steve. The Alpha jumped a little in shock before doubling down on his claim, pressing even harder almost everywhere that his body was in contact with Bucky’s— the hand over his lips, the grip on his left thigh, the knot in his ass. 

Lying there, bracing himself for the inevitable bite, Bucky knew that in Steve’s current state there was nothing left of the man but the Alpha. Bucky did not blame him. Instead, he mourned the loss of Steve’s right to make this choice. They had been reckless; hell— him much, much more so than Steve. Bucky was a _completely_ shit person. He had pushed Steve when Steve had expressed concern, said he didn’t want to get out of control when Bucky had no way of stopping him and—

_Oh._

Slowly, delicately, Bucky’s left thumb smoothed over the trigger of the Alpha tase, still strapped securely and accessibly around his grafted wrist. His silvered left arm was splayed limply in front of him, frozen in arousal-tinged terror like the rest of his body, but out of Steve’s sight. He _could_ stop the bite, stop Steve from tying them together for the rest of their lives and forever resenting Bucky for it.

All he had to do was press a button.

He could do it. _I should do it_, he thought. But Bucky could not convince himself. As his thumb hovered but remained immobile over the device, his mind was suddenly swimming with questions.

Why had Steve not bitten him yet? The Alpha had clamped down on Bucky with every part of his body _except_ his mouth. In fact, Steve had gone back to his feverish licking, the pheromone-laden saliva cooling Bucky’s hot skin and soaking into his scent glands while his cock continued to pump him full of come. Steve’s entire body was still strung tighter than a violin and the feral growling had never ceased, but Bucky remained unbitten and Steve was making no move to change that.

He knew that Steve could scent the anxiety on him (and probably also the confused arousal); the room had to be stinking with it. Why had Steve not tried to grip him yet, to calm him down while he claimed him? He could have done it with his jaw, even, given its proximity to the back of Bucky’s neck. But he wasn’t.

None of it made any sense.

The minutes passed; how many, exactly, Bucky could not say— five, ten, fifteen, maybe more. He felt the blood thrumming through the knot inside him the whole time. The skin over his scent glands started to feel almost raw from the unabated friction caused by Steve’s tongue. The Alpha’s body was as tense as ever, holding Bucky in a whole-body vice grip while Bucky’s thumb discreetly sat atop the tase trigger. But he wasn’t pressing it, and Steve—amazingly—still wasn’t biting him.

Bucky did not know how much longer they laid like that. Eventually, he could feel Steve’s knot begin to go down, and as the stretch in his ass lessened so, too, did the tension in Steve’s musculature. It was just little by little at first, and Bucky did not feel by any means that they were out of the woods, but he couldn’t help but feel the tiniest bit of relief creep up on him.

The knot was about halfway deflated when Steve very suddenly stopped licking. Bucky tensed, expecting the worst and fucking _pissed off_ that they had been so very, very close to breaking free of this problem.

For several seconds Bucky did not hear Steve breathe. The Alpha was completely still. The eerie silence sent a fresh bolt of fear straight through Bucky.

_This is it,_ he thought. He braced his thumb on the trigger.

But then, right at the same time that a flood of Bucky’s own fear scent reached his own nostrils, he heard a choked gasp from Steve followed by a high-pitched whine of unadulterated _terror_.

Bucky’s heart rate shot through the roof, but before he had time to react further there was an entirely different scent in his nose. Wait, no, _slamming_ into his nose, completely smothering his senses, like he was right on top of it and getting the full atomic blast. It was the most intense scent he had ever experienced, stronger even than Steve’s rut smell— but at the same timeit had a _lot_ in common with Steve’s rut smell and— _oh_— Bucky had smelled this before, familiar, all warm and safe and Alpha and—

The bedroom went black.

**Notes for the Chapter:**

> Oh no what happened to Bucky?!
> 
> We’ll unpack all of that action in the final chapter. 
> 
> CONTENT WARNING DETAILS (Spoilers):
> 
> Dub-Con - Established sexual relationship, but Steve's consent in this episode could be considered coerced. Everyone consents verbally but no one is clear-headed. Bucky and Steve are unprepared and under-educated about their urges due to circumstances out of their control. Both parties feel fear at some point or another. 
> 
> Potential Non-Con Elements: Steve has the ability to grip the back of Bucky's neck to force him to relax. Bucky is held down against his will by a feral Steve at the end of the chapter. However, it is clear to the reader that Bucky enjoys the sex overall.


	5. Act IV - Happy Ending

**Summary for the Chapter:**

> Bucky and Steve deal with the aftermath of the Heat.

**Notes for the Chapter:**

> Thank you to everyone who read this. Here is the final part.
> 
> I do intend on writing at least one sequel. I've fallen in love with this pair and there are other things I'd like to explore with them.
> 
> CONTENT WARNING: Heavy discussion (and recognition) of dub-con and non-con elements from previous chapter. No new warnings.

**Act VI - Happy Ending**

\---

Bucky Barnes woke up in a hospital bed.

Even with the fog of disorientation filling his head like a giant ball of cotton, Bucky recognized the sights and scents of a sterile medical environment almost as soon as he opened his eyes. He could also see that it was dark outside. Clumsily, Bucky began to rifle through his own memory in an attempt to find some indication as to what had landed him in a hospital bed to begin with, but he found nothing. Bucky’s brain completed a full body scan and found that, all in all, he felt fine, no notable issues or aches or pains— well, aside from the dull throbbing in his ass.

And that’s when Bucky remembered.

His hand shot up to his neck, feeling around the scent glands. He was relieved to confirm that there was no bondmark. _That’s good_, he thought. That meant that Steve had done it; he’d successfully resisted a frightening and primal urge to bite Bucky in his Heat.

But creeping through his relief Bucky felt the thick ooze of guilt returning to him. The whole thing had been _his_ fault. He had disregarded Steve’s concerns and pushed the Alpha into something that Bucky knew Steve wasn’t comfortable with. Even more egregious, Bucky had used Steve’s own biology as a weapon against him as a means for Bucky to get what we wanted.

_Oh, god, Steve._ Where was he now?

Bucky carefully pulled himself up into a sitting position, groaning a little at the stiffness in his neck. He looked around the sad, beige hospital room but did not find Steve. Instead, he found that he was alone save for one other person— a familiar-looking redhead he knew by the name of Black Widow, situated in an ugly blue visitor’s chair on the far corner of the room. She was in her street clothes.

“Good evening, sunshine.” When she smiled at him, Bucky was taken aback with how unexpectedly warm it was.

The two of them had never met before—though Bucky knew she and Steve were close friends— but Bucky didn’t have the wherewithal to stop and ask what one of the most successful espionage agents of all time was doing in his hospital room. At night.

“Where is Steve?” Bucky demanded instead, panicked. “Is he— is he okay? Can I see him?”

Natasha furrowed her brow at his request, concerned and a little curious. She calmly stood from her chair and moved to Bucky’s bedside.

“You _want_ to see him?” she repeated. “Are you sure that’s a good idea?”

“Please,” he begged. “I just want to talk to him, tell him I’m sorry, I’m _so_ sorry—”

“Bucky—Bucky, wait. Slow down.”

Bucky forced himself to shut up and take several deep breaths.

“First off, do you know who I am?”

Bucky nodded and sniffed. “You’re the Bla— You’re Natasha Romanov. You’re Steve’s friend.”

“That’s right,” she replied. “Bucky, I need you to tell me what you remember.”

And for some reason, although she was basically a stranger to him and he _still_ didn’t know why she was in his hospital room, Bucky found that he instinctively trusted her. She was close enough to smell, now, but Bucky found that he couldn’t pinpoint her designation; she must have been wearing scent blockers.

“What I remember about—?”

“What you remember about earlier today,” she finished for him. “About what happened after you and Steve woke up in your apartment.”

So, painfully, Bucky began to recount his memory of the day. He was surprised to find that all of his memories were intact, since he had half-expected to find black holes where his hindbrain had taken over control. Bucky related how the Heat had taken them both by surprise, how Steve had begged Bucky to keep away because the Alpha did not know if he could control his urges. He hung his head in burning shame as he admitted how he had coerced Steve, chipped away at his resolve until he finally just gave into Bucky.

When he got to the part about producing the Alpha tase, how he had worn it to make Steve feel better but never thought that he would ever _need_ to use it, his heart suddenly leapt for fear in his chest.

“I— I didn’t use it, did I?”

Natasha gave him a look, a little sad, but a lot knowing. She shook her head.

“No, you didn’t. At least, Steve didn’t mention it.” She let out a humorless laugh. “Doesn’t seem like something he would have forgotten.”

Hearing that made Bucky experience a complex sense of relief. Now that he knew that Steve had _not_ bitten him, he was selfishly glad that he had stuck with his gut feeling and never set off the tase—

but he also knew that he should have done it _anyways_ to keep his promise to Steve that he would protect himself.

He quietly continued on with his story.

“For almost the entire time, everything was good— _god_,” he blushed, “everything was _amazing_. Steve was perfect, just the way I knew he would be. But…” Bucky trailed off with a mournful sigh, squeezing his eyes shut to the pain of the memories that came next.

“His rut went feral,” Natasha supplied for him.

Bucky nodded.

“I didn’t even know that could really happen. I thought he was going to _bite_ me, to bond us.” Bucky gave a little sniff and wiped his running nose with the collar of his hospital gown. The grief inside him suddenly turned to anger. “He told me he never wanted to feel like he was out of control and I _pushed_ him, Natasha! Steve is so fucking good to me and I _ruined_ it!”

The tears that been threatening the inner corners of his eyes began to fall freely now.

“Hey, hey,” she cooed. In the back of his brain Bucky was a little shocked at how motherly the goddamn Black Widow could be. “It’s okay, Bucky. Do you know why you’re here, in the hospital? How you got here?”

Bucky shook his head; he really didn’t.

“Steve brought you in at fourteen-hundred hours earlier today. You were unconscious, but otherwise unharmed.”

Bucky stared, not really knowing what to make of the information. Natasha took it as her cue to continue.

“All I can tell you is what Steve told me, and what I saw after I arrived here. Steve said that you had fallen asleep together at your home last night and that when you awoke this morning, you were in a Heat. He said you had expected this might happen—went off your suppressants so that it would—but your doctor had indicated that it would not come for another three months, at least. You were planning to spend it together when it did happen.”

He nodded. “Right. But when I woke up like that and Steve’s rut had started, too, he realized what was happening and he freaked _out_, Natasha. He was _so_ scared. He said he thought he might hurt me if he stayed with me.”

Natasha hummed in understanding. “Steve’s never had a rut before; most Alphas never do. And this rut, if you believe what the doctors here have to say, was not exactly normal.”

Bucky listened, his cheeks burning with shame to think about how much he had hurt Steve.

_God, I am such a shit person._

“Look, Bucky… Steve feels that this was his fault for taking advantage of you in your Heat.”

Bucky’s eyebrows shot up and a protest quickly formed in his throat, but Natasha silenced him with a look.

“He said that after you two... tied, he blacked out and went feral at some point, tried to bite you— mark you. He said that when he started to snap out of it, he realized that he had you pinned on the bed, felt you were shaking and terrified.”

His heart ached to remember the moment when Steve had begun to come around, when his knot deflated.

_He was _so_ scared. I did that to him._

Natasha continued. “It sounds to me like he was still halfway feral when he noticed all of this, and did the only thing he could think of. He, uh.” Natasha’s tone suddenly shifted a little, almost humorous, and Bucky watched as she rubbed her face and blinked away something like incredulity. “Steve freaked and scented you with Alpha calm so hard that it knocked you _out_.”

It took Bucky a long moment to comprehend this information, but the more he thought about it— and thought back to rutting Steve, how he had been overcome by all of the new things he’d learned his Alpha body could do— the more Bucky understood.

“And then Steve took me here,” he finished.

Natasha nodded. “You were unconscious but you were still in Heat, and Steve—Steve was a _mess_. Still is, actually. Sounds like he threw on some clothes and _ran_ here, carrying you, ten city blocks.” And at that Natasha did smile, all humor and a little fondness. “But I guess no one should expect anything different from Steve Rogers.”

The mental image did make Bucky laugh a little. It felt good, like something was loosening in his chest.

“When he got you here— still in rut himself, of course— he was panicking, running around and trying to get every doctor to look at you. But then when they tried to take you and treat you, Steve _freaked_. He wouldn’t give you up.”

“_Seriously_?” Bucky asked. He couldn’t deny the tingle of warmth he felt at the thought of Steve, both possessive and also obsessing about Bucky’s well-being, but then he reminded himself— Steve was only like that because Bucky had hurt him and made him feel fear. 

“Yeah, seriously.” Natasha shifted back to a more clinical tone. “Around that time your doctor arrived; the hospital had identified your records and called your Dr. Harlow—called himself Pete— and when he got here he told the staff what he believed was happening. When they realized that they were dealing with an exceptionally dangerous rut, they took him down with a truckload of sedatives before injecting him with an emergency rut suppressant. After they got him tame someone called Tony, and Tony called me. By the time I got here the doctors had decided to keep you under artificially while they gave you IV suppressants to halt your Heat.”

“Where is Steve now?” Bucky asked.

“He went back to your apartment a few hours ago. No, sorry, I know what you’re hoping— it wasn’t so he could sleep. After they got him tame, he wasn’t in rut anymore, but he wasn’t exactly calm either. He kept asking the doctors how you were, where you were, if you were hurt. He knew he didn’t bite you but he was convinced that he had hurt you in other ways. The doctors assured him that you were fine, no injuries and no sign of forced entry, just a normal amount of bruising. But he didn’t believe them, thought they were lying to him to keep him from freaking out further.” Natasha shook her head as she spoke, apparently in disbelief at her own story. “That’s when he ran back to your apartment, saying he needed to check the sheets for blood.”

“He won’t find any,” Bucky murmured. His head was spinning.

“I know. But I told him to grab some clothes for you while he was there, so you have something to leave in. He, uh... didn’t exactly dress you before he brought you here, just rolled you up in every blanket he could find. According to the intake staff he came in with what they’ve now termed an ‘Omega Burrito’.”

“Oh _god_,” Bucky laughed, burying his face in his hands.

After their laughter died down Bucky sat quiet for a long while, absorbing the information and just stopping for a moment to comprehend the cumulative whirlwind of the day’s events. When spoke again, it was nothing above a whisper.

“He never bit me,” Bucky said. “He _was_ feral, he was out of his goddamn _mind_ there at the end. But he didn’t bite me.”

Natasha smiled softly and gave him a wink.

“I guess there’s more to Steve Rogers than Steve gives himself credit for,” she said, patting his leg. “Now, get some more sleep. Take some time to think. I’ll tell Steve you want to see him in the morning.”

Natasha dimmed the lights as she exited the room.

Exhausted, Bucky shut his heavy eyelids and let sleep take him. 

—

When Bucky awoke the second time, he was greeted by the makings of dawn falling softly through the cream-colored window blinds. He sat up to take in his surroundings again.

Natasha was gone. But Bucky was not alone.

In the chair on the opposite wall there sat one very distressed-smelling Steve Rogers. He was bent over in the ugly chair with elbows on his knees, eyes down, fingers carded through his dark blond hair. He wore the same clothes he’d been wearing when he came over to Bucky’s the night before his Heat hit. All in all, he looked a _mess_. Bucky’s heart ached anew with grief and guilt.

“Stevie?” he choked out. The tears were coming almost as soon as he’d said the name aloud.

Steve’s head shot up. His eyes were wide, bloodshot red, and the skin of his cheeks appeared salted and pink. Stung by dried tears.

The near-panicked Alpha stood up instantly, before seeming to think better of his quick movements, as though he was worried he might scare Bucky away from him. Steve steadied himself in place and made a sad attempt at clearing his throat.

“Buck?”

And the broken sound of Steve’s voice had Bucky’s chest flooded with an assault of different emotions. He wanted to dash across the room and wrap Steve in his arms, whisper in his ear that everything was going to be okay, that they could fix this, together— but he also wanted to grab Steve and _shake_ him, tell him he deserved better than Bucky, that he shouldn’t be here worrying about a man who had refused to acknowledge his pleading and protesting.

“Please,” Bucky begged instead, holding out his arms towards Steve. “Please baby, just— come here?”

He watched the relief crash over Steve, who then rushed towards Bucky and into his inviting arms. Bucky let out a fragile exhale of joy and alleviation to be touching Steve again.

As happy as the Alpha looked and smelled to be allowed near Bucky again, he could tell that Steve was straining to keep his hands to himself. He sat on the edge of the bed and let himself be held, leaning his weight into Bucky’s and tucking his large frame into Bucky’s smaller one— carefully avoiding putting his face against Bucky’s neck. But Steve would not use his hands to touch. This made Bucky very unhappy; he just wanted his Alpha to hold him. But he didn’t push, just moved his hand up to run his fingers through Steve’s tousled hair.

“Stevie,” he said again, whispering it over and over again like Steve’s name was Bucky’s own little mantra. He closed his eyes and inhaled the scent of the other man; it was warm and familiar, if not still laced with distress. “I’m so happy you’re here, Stevie. So _happy. _I was afraid you might be gone, can’t believe you still—”

But Bucky was cut off by a deafening dry sob heaved into his shoulder. Steve lifted his face (_god_, he looked so exhausted) and locked pleading eyes with Bucky’s. For a moment, Bucky’s entire everything was focused only on the stark contrast of crimson rims, wet blonde eyelashes, cerulean irises— his whole world over just red and white and blue.

“_Buck_,” Steve started, voice still broken and breaking more with every sound. “I’m so sorry— _so_ sorry, baby. I never wanted to hurt you. _Never_. I should have done better, I _could_ have done better, I didn’t try hard enough to fight it—”

“—Steve, stop—”

“— _knew_ I was gonna wanna bite you, knew it from the moment I woke up, should’a told you—”

“_Steven Grant Rogers_, you shut the hell up right now.”

The stern growl from Bucky finally silenced Steve, who snapped his mouth shut and began to hang his head low, shamed. But Bucky— who would be having _none_ of that— grabbed Steve’s chin and forced his eyes back up.

“Stevie, baby— baby look at me, okay? Eyes on me.”

Bucky waited for Steve’s glance to stop its anxious flitting around before continuing.

“This was _my_ fuck-up, alright?” He stopped briefly to silence another protest from Steve. “No— Steve, stop it. I need you to listen. Just listen. Look… I’m the _only_ one here who should be sorry. You saw all of the warning signs and you spoke up, and _I_ was the one who told you to ignore them. You didn’t do anything wrong, Steve. Do you understand?”

Steve, who clearly wasn’t convinced, just waited until Bucky was done talking to dive back into his sea of self-hatred.

“I _did_ though, Buck. They said I went _feral_, I tried to _bite_ you!”

“But you _didn’t_ bite me,” Bucky demanded. “Did you, Steve?”

Steve looked to swallow a retort, before shaking his head instead.

“Look I— god, I _never_ should have pushed you the way I did,” Bucky went on. “That wasn’t right at all. I wasn’t respecting the choices you wanted to make. But what I said about you, baby? I wasn’t wrong. Feral or not, I knew— I _know_ you could never hurt me.”

Finally it looked like Bucky might have Steve’s ear, which caused a strange conflict of feelings in Bucky’s head. On one hand, he was happy to see Steve listening, looking like he might actually be considering what Bucky was saying. On the other hand, it hurt Bucky’s heart to think that Steve might just be reaching, desperately, for _one good thing_ he could still believe about himself. Bucky inhaled quietly and continued.

“I know you weren’t all there in the head, but I remember the whole thing, baby. You were fighting every bad urge and you weren’t letting up, I could _feel_ it. I’ve never seen you more tense; I just wish I could have been outside of my body and been able to hold you through it. But you didn’t _do_ it, baby— you _never_ let yourself bite me.”

Steve stayed silent for a long while afterwards, brow furrowed, considering Bucky’s words. He idly ran the pad of his thumb back and forth over the back of Bucky’s metallic hand where their fingers were laced together. Bucky closed his eyes and let himself enjoy the sensation. 

After a while Steve finally spoke. “Why didn’t you use the tase?”

And Bucky had been fearing this question. The answer was... complicated. It involved Bucky having to admit that he had selfishly considered that he might want to be bonded to Steve, even though they had only been together for two months. He didn’t want to scare Steve any further with such a big admission, so for now, he settled on the half-truth.

“I thought about it,” Bucky said. “I really did. But I— I just really didn’t believe that you could hurt me. And, hey.” He tilted Steve’s bearded chin up again. “I was right, wasn’t I?”

Steve gave him a small smile and nodded. Looking for something to break through the tension a little, Bucky tilted his head forward to nip playfully at Steve’s bottom lip. The Alpha chuckled and shivered.

“It was all just an accident, Stevie. Okay? We’ll do better next time, now that we know what we’re in for. We can figure it out.”

Steve’s eyes went wide at that, shocked and maybe a little mortified.

“_Next_ time? You want there to be a _next_ time?”

“Only if you want it, Steve,” Bucky interjected quickly. Never again was he going to push Steve into something he wasn’t ready for. “And it’s okay if you don’t— it really is. We can figure that out, too. But for my part? _God_, Steve.” Bucky closed his eyes and released a tiny, quiet moan at the returning memories. “Spending a Heat with you was _amazing_.”

Bucky didn’t miss how Steve’s lips flushed red and how the Alpha’s breathing picked up as he listened to his words.

“Yeah, Buck?” Bucky took it as a cue to continue.

“I can’t even begin to _describe_ it, Stevie.” He donned a flirtatious grin and lowered his register before continuing on his mission to massage the Alpha’s ego, to make him feel like he had worth again. “Everything you did to me was incredible: the way you kissed me, the way you handled me, the way you _fucked_ me. And the way you went so damn _wild_ for me, baby... Almost embarrassing to admit how much I loved your animal side.” He punctuated the statement with a kiss and a nip to the angle of Steve’s jaw. “Loved getting it rough from you. I’d be crazy to not want it all again.”

Bucky inwardly gave himself a little high-five as he watched the effects of his graphic prose unfold across Steve’s face. Everything he’d said had been true; in fact, Bucky had half the mind right then to dive forward and eat Steve alive there in the hospital room— however emotionally inappropriate that might be at the moment.

Steve gave him a heated look. Just as gravity in the space between their bodies started to become weirder, pulling them together, the previous tension in the room making way for something more viscous, an unexpected voice shattered their bubble.

“How’s everyone doing this morning?”

Both Steve and Bucky jumped a few inches apart as Dr. Pete entered the room. The familiar man wore a white coat, but Bucky could see a more casual sort of Sunday attire beneath it.

“Better, Dr. Pete,” Bucky said, directing a genuine smile back to Steve. Steve returned it.

Bucky pulled Steve over to sit next to him on the bed and laced their fingers together, turning their attention towards the doctor, who had the look of a man with important information to share.

“Good! That’s good to hear. The two of you had quite the day yesterday.” Dr. Pete set his heavy clipboard on the table. “Well, first off, I believe an apology is in order. Nothing in all the medical literature in the world would have predicted that ‘three to six months’ might turn into eighteen hours.”

And Bucky _might_ have noticed Steve glowering at the doctor, just the tiniest bit. It occurred to him that the Alpha maybe blamed Dr. Pete’s advice a little (or maybe a lot) for what had happened, but Bucky would allow it— as long as Steve played nice, and as long as he wasn’t directing that blame at himself anymore.

“Honestly, doc, I’m just glad that you haven’t yet placed a restraining order against me on Bucky’s behalf,” Steve joked awkwardly. Bucky was happy to hear Steve attempting to find a little bit of humor in the situation.

“On the contrary, Mr. Rog— Captain.”

The Alpha chuckled. “You can call me Steve.”

Dr. Pete smiled but gave them an unsure look before carrying on.

“Well, on the contrary, Mr. Rogers,” and Bucky had to bite his lip to keep from laughing at Steve’s eye roll, “I would venture to say that a large majority of the medical community is very interested in you and Bucky remaining a pair.”

Bucky shot him a curious glance. “What do you mean by that?”

Dr. Pete took a seat and grabbed for his heavy-looking clipboard. “Well, we’ve run some blood tests on the two of you since you were admitted. Mr. Rogers, you indicated yesterday that you and Bucky completed a home test, and the results were out of range— correct?” Steve nodded. “Home tests are obviously limited compared to tests we can run in a laboratory setting, but the fact that you fell over the sixty-percent mark was... Well, _interesting_ to me, but not surprising. I suspected something to that effect might be in play when I diagnosed Bucky’s symptoms this past Friday.”

Bucky and Steve looked at each other, wondering where this was going.

“So last night, we submitted your blood samples to the laboratory, where we can achieve much higher quantitation limits and drill down into your Compatibility rating to one hundredth of a percentage point.”

“Wow,” Steve mumbled, clearly impressed. Bucky sort of loved his face when he was marveled by new feats of twenty-first century technology. “So where do Bucky and I fall, doc?”

“Well that’s the even more interesting bit. We already knew that you were a highly Compatible pair, based on the home test— but our laboratory analytical results further indicate that the two of you are quite _exceedingly _Compatible.”

Bucky just stared, a little blankly.

Steve pressed further. “What does that mean? You got a number for us?”

“I do not, Mr. Rogers.”

Steve shot Bucky a confused look.

“Maybe we misheard you, Dr. Pete,” Bucky interrupted. “I thought you said you _ran_ the tests.”

“We did. It’s just that the cumulative concentration of your Compatibility factors exceeded the upper quantitation limits of the machine.” Dr. Pete paused for a beat. “Seven machines, actually.”

_Oh._

“Okay, so then it’s like with the home test,” Steve reasoned. “Too much to count. Out of range.” It made Bucky think back to his kitchen table two nights ago, when he and Steve had hugged and kissed and smiled at reading the results of the boxed test.

“Yes.” Dr. Pete nodded. “But also— not quite the same. The quantitation limits of the laboratory method are _much_ higher than the limits of the home test.”

“How high?” Bucky asked. His heart beat heavy against his ribcage. _Where the fuck is this going?_

Dr. Pete grabbed his clipboard and flipped back a couple of pages. “The practical quantitation limit of the method is 97.65% Compatibility.”

Bucky’s heart leapt up through his throat and out of his skull and up into the hospital room ceiling.

“Okay,” Steve said, his voice a little shaky and eyes wide as saucers. “So, what you’re saying is that Bucky and I are… more than that.”

Dr. Pete nodded. “When I said you were exceedingly Compatible, I meant it. Your markers have literally exceeded our ability to quantify them.”

Bucky’s head felt like it was spinning off of his _head_. He looked over at Steve and found that the Alpha didn’t look to be faring much better.

“So, what?” Bucky asked. “We’re like some kind of super couple?”

“That might not be a bad way to put it, actually. Although the academic community will probably find a different term.”

“Is that why the Heat and the rut were so intense?”

The doctor nodded. “I’m positive that’s the reason.”

“Leave it to you to have a super solider rut,” Bucky said to Steve, nudging him teasingly with an elbow. He regretted the words almost as soon as they came out of his mouth; it occurred to him that Steve had probably been thinking up until that very moment that some sort of serum-related effects must have precipitated his feral state.

But Steve just smiled and elbowed him back.

“I also believe that your high— _very_ high— Compatibility was the reason Bucky went into Heat so quickly after we deactivated the suppressant,” Dr. Pete continued. “Bucky, Mr. Rog— Steve, you should know that there is no recorded case of Compatibility as strong as yours; the closest ever observed prior to now was just 72.3%, which was previously thought to be astronomically high considering what we know about average Compatible pairs. Unfortunately, this means that we are now in uncharted territory concerning the physical manifestations of the effects.”

Steves eyes went wide, and Bucky squeezed his hand harder. They were both starting to understand why almost every detail about the day before had been a shock to their systems, and Bucky tensed to think that the uncertainty might just keep on coming in the future.

“For example,” Dr. Pete continued, “studies have worked for a long time to model the effects of Compatibility factors on physical manifestations of Heat and rut, but every model we could possibly run with the surrogate input of 97.65% suggested the same thing.” Dr. Pete turned to look at Steve. “Mr. Rogers— The fact that you did not place a mating bite on Bucky when you had the chance _should_ have been mathematically impossible. Or, at least, astronomically improbable.”

_What the fuck?_

“What does that mean?” Bucky asked instead.

“It just means that the models are flawed. Like I said, we are in uncharted territory, and there is likely to be a lot learning as we go in the future. For that, we’d like to occasionally monitor the two of you to better help us understand your qualities from a medical view.”

Bucky didn’t exactly like the idea of a bunch of white coats poking him and Steve like test subjects, but he also figured the alternative was worse; as an engineer, he knew information was power.

“However,” Dr. Pete said, setting down his clipboard once again, “moving forward, there _are_ a few things I can say with confidence—things that should be true for all Compatible couples, even scaled up to infinity on the Spectrum.”

“Okay,” Steve nodded. He seemed encouraged by the idea of knowing something—anything— for certain, after what they’d been through. “What are they?”

“First— if you were ever to decide to make the bond, the urge to bite would obviously disappear after the fact.”

This wasn’t exactly news to Bucky; he had learned as much in high school health class. Judging by the straight-faced nod he saw from Steve, the Alpha had also been aware of this. The two of them shared a look in silent agreement that they would table that discussion for later.

Hearing no questions, Dr. Pete continued. “The second thing I can assure you is that— provided the two of you remain in each other’s lives— you _will_ find yourself spending your Heats and ruts together. Based on the incredible and unique things I’ve seen in your blood-work, I am positive now that the two of you won’t be able to— and would not _have_ _been_ able to— separate yourselves during Heats; Mr. Rogers would likely hurt himself or others trying to return to you, Bucky, and you yourself would remain in a dangerously distressed state. Unfortunately, I can’t say for certain that we will be able to find a long-term Heat suppressant that will work for you, given the way your body will burn through them in the presence of such an extremely Compatible mate, but even if we _do,_ you will still occasionally need to cycle through the occasional natural Heat. This will all hold true even if you complete the bond— and perhaps even more so if you do.”

Steve grip on his hand tightened, and Bucky could scent the tension in his body. He felt a deep pang of sympathy for the Alpha at the thought that he was almost guaranteed to lose control again—like it might even become a staple of their life together. Bucky couldn’t deny it— he had _loved_ wild Steve, even feral Steve; but the thought of how helpless it would make Steve feel being forced to experience that so frequently broke Bucky’s heart.

“But the last item, I think, is good news.” Dr. Pete set down his clipboard and smiled warmly, leaning towards them.

_Fucking_ finally, Bucky thought to himself.

“Regardless of whether you bond, Mr. Rogers will _not_ be experiencing another rut with quite that same degree of control loss.”

Bucky both saw and smelled the wave of relief that washed through Steve. It felt like a weight had been lifted off of the entire room.

“That’s not to say that he won’t still experience quasi-feral effects—it’s possible that may always happen—but the _intensity_ of the effects will likely exhibit something of a half-life. They should be reduced with each coming rut before they eventually level out to a predictable, perhaps manageable level.” He turned to Steve. “I find it extremely unlikely that you will ever again have to fight the same degree of feral urges you battled yesterday. The worst of it, I think, is behind you forever.”

And Steve’s scent, which had at the least been tinged with the sour of anxiety all morning (and at most, smothered), finally returned to the warm scent of charcoal and dried tea leaves that Bucky loved so much. He pulled Steve’s hand up to his lips and kissed his knuckles with a little smile.

“See, baby? It’s gonna be okay. We can do this.”

Steve face’s split into a grin, and Bucky let himself be pulled to standing and— _finally_— into the crushing embrace of his Alpha’s strong arms. Bucky didn’t care if Dr. Pete was there witness to their intimate moment; this truly was incredible news for them both.

“I’m putting in papers to discharge you today, Bucky. We’ll make appointments to have you come into my office once a month leading up to your next heat; I’d like to keep track of your hormone levels, at the very least, for your own sake.”

“Thank you, doc,” Steve said, giving a nod to Dr. Pete.

“Of course. Enjoy each other,” Dr. Pete winked. “What you have is very, very special.”

Both he and Steve thanked the doctor one last time as he turned to leave the room. When he was gone, Steve lifted Bucky up and brought him back down in his lap, kissing him for all he was worth.

For a long while, the two of them sat that way on the hospital bed and simply drank each other in. Steve finally let himself bury his nose in Bucky’s neck, inhaling the Omega’s scent— _his_ Omega’s scent— and Bucky knew he must getting a delicious mix of them both after the dutiful scent marking he had undergone during the Heat.

“Wanna lay down?” Bucky whispered.

Steve nodded and pulled them down onto the bed, smiling the whole way.

—

A couple hours later found Bucky dressed, waiting with Steve in the hospital room for the discharge nurse to stop in and give them the official notice of Bucky’s release. They were still curled up on the too-small bed like teenagers, facing each other on their sides and basking in the warmth of full laughs and tiny kisses. Bucky was thankful that levity had returned to them with such ease after the dark twenty four hours that had preceded.

Steve’s hand wandered down Bucky’s back and over the curve of his behind through the sweatpants. He knew the motion wasn’t particularly sexual; Steve had been (mostly subconsciously) fawning over him like a mother hen ever since Dr. Pete left, looking Bucky over for bruises (there were definitely a few to speak of), asking Bucky again and again if that part hurt, if this part hurt, if he needed food or water. Bucky both rolled his eyes and shuddered to think that Steve would probably be like this, but to a _greater_ extent in the future every time they shared a Heat again.

“Careful down there, soldier,” Bucky teased as Steve gave one of his ass cheeks a light, playful squeeze. “My ass is still needs to be sewn back together after what you did to it.”

He made sure to give Steve a wink to clearly let him know he was kidding— he did _not_ want to deal with Steve freaking out over the condition of Bucky’s ass on top of everything else. Luckily for him, Steve just laughed.

“Well, from what I remember— and yeah, I _do_ remember that part— you’re weren’t complaining about it at the time.” Steve trailed off and leaned in closer, chapped lips brushing teasingly over Bucky’s. “In fact, I seem to remember that you couldn’t get me inside you fast enough.”

Bucky shivered.

“Hm… maybe,” he grinned back.

They sat in silence for another moment, Steve just petting Bucky while Bucky scratched his fingernails through Steve’s beard. When Bucky spoke again, it was more somber.

“I’m just glad you don’t have to remember the bad stuff. I don’t wanna think about you being haunted by things you did that weren’t your choice.”

He tucked a strand of just-too-long hair back behind Steve’s ear.

“I remember some of it,” Steve admitted quietly after a moment. He pulled Bucky closer in and gently buried his nose against Bucky’s neck, letting himself be naturally calmed by the scent of his Compatible partner. “It doesn’t really feel like they’re my memories, though—it’s like I blacked out at the end and had to watch some other Alpha take over my body.”

Bucky remained silent but began massaging his fingertips lightly into Steve’s scalp, waiting for him to continue.

“I think— I think I remember trying to stop him—trying to fight him. I remember it wasn’t easy. I could still feel what he was feeling, and he wanted you _bad_, Buck. Scary bad. He wanted to do more than just to bite you, baby, more than even— more than even just to breed you— he wanted to _possess_ you. He wanted to take over your body, your mind, wanted to occupy the same space that you did, all the time, everywhere. He wanted to crawl inside your _skin_. Knowing how he was thinking, what he wanted— it was the most scared I’ve ever been in my life.”

When Steve finished the room fell quiet. Bucky willed himself to keep from shivering. For a long moment, they simply held hands and listened to the back and forth of each other’s breathing.

“How did you do it?” Bucky asked, breaking the silence.

“Do what, Buck?”

“You won,” he said. “You fought him, and you _won_. How did you do it?”

Steve pulled back from Bucky’s neck with the smallest of laughs and a little shrug. “Guess I just told him to screw off and he listened— eventually.”

Then Steve moved his hand up to Bucky’s face and lowered his voice to almost a whisper. Bucky leaned into the warmth of Steve cradling his face and let his eyelids slide shut.

“Told him I wasn’t gonna let him hurt the man I love.”

Instantly, Bucky’s eyes were open again. Wide open. His whole body came to life at Steve’s words.

“You what?!” he responded, voice nearly at a shout but cracking, too, filled with ecstatic glee.

Steve was still smiling at him.

“I love you, Buck.”

Bucky’s mind reeled with about a million different things he could do or say in response. But he landed on just two of them.

First, he placed his hands on either side of Steve’s face, the larger man’s strong jaw and thick beard making Bucky’s fingers look almost small. He looked Steve square in the eyes.

And then he said,

“I love you, too, Stevie.”

And he did. 

Moments later, the two of them curled further into each other and, floating but exhausted, let themselves doze lightly while they waited on the nurse.

Bucky Barnes fell asleep with a smile on his face and the man he loved in his arms.

—

_Fin._

**Author's Note:**

> I'm on Tumblr <3 [@the1918](https://the1918.tumblr.com)


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